Bugs and spiders in Massachusetts
Massachusetts has a long indoor list, and the Asian lady beetle sits far above everything else in the record counts. Eastern carpenter bees, western conifer seed bugs, tan jumping spiders and bold jumping spiders follow. All four of the ticks on this page are established here, and American and German cockroaches are Common as well.
Get advice if bitten
These are found in Massachusetts. If you think one bit or stung you, call Poison Help at 1-800-222-1222; call 911 for trouble breathing or swelling.
Common in Massachusetts
Established here or recorded often, most-recorded first.
Asian lady beetleBe carefulCommon · 11,685 records
Eastern carpenter beeBe carefulCommon · 4,893 records
Western conifer seed bugHarmlessCommon · 3,387 records
Tan jumping spiderHarmlessCommon · 3,103 records
Bold jumping spiderHarmlessCommon · 2,968 records
Brown marmorated stink bugHarmlessCommon · 2,532 records
Black carpenter antHarmlessCommon · 2,508 records
Spotted lanternflyHarmlessEstablished · 2,424 records
Eastern yellowjacketBe carefulCommon · 2,199 records
Rough sowbugHarmlessCommon · 2,140 records
European paper waspBe carefulCommon · 1,708 records
American dog tickGet adviceEstablished · 1,617 records
Zebra jumping spiderHarmlessCommon · 1,172 records
Blacklegged tickGet adviceEstablished · 1,164 records
Yellow garden spiderBe carefulCommon · 1,136 records
House centipedeBe carefulCommon · 1,134 records
Boxelder bugHarmlessCommon · 834 records
European earwigHarmlessCommon · 801 records
Greenhouse millipedeHarmlessCommon · 772 records
Varied carpet beetleHarmlessCommon · 746 records
Woodlouse spiderHarmlessCommon · 719 records
Pavement antHarmlessCommon · 714 records
Dark fishing spiderBe carefulCommon · 645 records
Northern black widowGet adviceEstablished · 367 records
Spotted orbweaverHarmlessCommon · 353 records
Long-bodied cellar spiderHarmlessCommon · 347 records
Odorous house antHarmlessCommon · 250 records
Broad-faced sac spiderBe carefulCommon · 233 records
Indianmeal mothHarmlessCommon · 215 records
Lone star tickGet adviceEstablished · 212 records
Common house spiderHarmlessCommon · 198 records
American cockroachBe carefulCommon · 175 records
Northern yellow sac spiderBe carefulCommon · 99 records
Fruit flyHarmlessCommon · 97 records
German cockroachBe carefulCommon · 65 records
Greenhouse camel cricketHarmlessCommon · 57 records
Barn funnel weaverHarmlessCommon · 48 records
SilverfishHarmlessCommon · 43 records
Brown dog tickGet adviceEstablished
House mosquitoBe carefulEstablishedWhat to watch for in Massachusetts
Start with ticks. The blacklegged tick can spread Lyme disease and several other serious infections, the American dog tick can spread Rocky Mountain spotted fever and tularemia, and the lone star tick can spread ehrlichiosis and is linked to alpha-gal syndrome. The brown dog tick is listed as established too, though it mainly feeds on dogs. Take a tick off promptly, and watch for rash or fever in the weeks after.
The northern black widow is established in Massachusetts. Medical advice is the right call for a suspected bite, because a bite from an adult female can cause spreading pain and cramps, and Poison Help at 1-800-222-1222 can talk you through a worrying one. The southern black widow has only a handful of records and is not known to live here. Eastern yellowjackets, European paper wasps, and house centipedes are the Be-careful species people run into most, along with American and German cockroaches indoors.
Through the year
- Spring
- Rough sowbugs and pill bugs turn up after wet spells, carpenter bees begin their drilling, and American dog ticks reach their peak in late spring.
- Summer
- Blacklegged tick nymphs, the stage most linked to Lyme disease, peak in early summer, and spotted lanternfly adults appear from July.
- Fall
- Asian lady beetles arrive in October and November, with western conifer seed bugs and brown marmorated stink bugs coming in from late September.
- Winter
- Warm days bring lady beetles and stink bugs out at windows, and Indianmeal moths are most often noticed indoors in these months.
Seen now and then
Recorded a few times; often brought in on plants, firewood or luggage.
Webbing clothes mothHarmlessOccasional · 24 records
Oriental cockroachBe carefulOccasional · 19 records
Black carpet beetleHarmlessOccasional · 19 records
House flyBe carefulOccasional · 19 records
FirebratHarmlessOccasional · 17 records
Brown-banded cockroachBe carefulOccasional · 12 records
Bed bugBe carefulOccasional · 11 records
Drugstore beetleHarmlessOccasional · 9 records
Southern house spiderHarmlessOccasional · 6 records
Camel crickets (native)HarmlessOccasional · 4 records
False black widowBe carefulOccasional · 3 records
Agrarian sac spiderBe carefulOccasional · 3 records
Pharaoh antBe carefulOccasional · 3 recordsRecorded, not established
Range maps don't place these here, but people have recorded them. Usually hitchhikers.
Lists come from research-grade iNaturalist sightings (Massachusetts: 756,962 arthropod records) and, for dangerous species, published range maps. A species with few records may be a hitchhiker. Counts pulled Oct 18, 2026.

