THe HyMENopTEeRA OF MINNESOTA 205 
with chewed insects for from 8 to 15 days, or to the end of their larval 
life. They do not store up food, and colonies persist for only one sea- 
son. In the more common species, nests consist of comb and envelop- 
ing layers made of a papery material secured by scraping wood fiber 
from weather worn boards and posts and mixing it with a salivary 
secretion. They will take paper itself when sufficiently wet and pulpy. 
Here occur our “yellow jackets” and “hornets.” These particular 
insects are fond of meat and are attracted to exposed beef carcasses 
in butcher shops and elsewhere. 
BETHYLIDAE 
Wings not folded longitudinally in repose; wings may be absent or reduced; no 
constriction between first and second abdominal segments; discoidal cells obsolete, or, 
if the first is present, it is petiolate; head oblong; antennae with twelve or more 
joints; fore tarsi of female never chelate. 
For an interesting account of the life his- 
tory, ‘ot “a ‘Bethylid, see Howard's “Insect 
Book” p. 34, where Mr. Busck’s observations 
upon Laelius trojodermatis Ashm., parasitic 
on Dermestid larvae, are published at some 
length. 
Pseudisobrachium myrmecophilum Ashm. 
lives in ant nests, as does also P. mandibulare 
Ashm. Neoscleroderma tarsalis Ashm. 1s 
YG -TOPUS-tamen parasitic on Silvanus surinamensis. Other 
Fig. 91. Gonatropus flavi. {fOrms are parasitic in various beetles. Go- 
itor ed) SNut. Mus. “niozus sp. is parasitic on the codling moth. 
DRYINIDAE 
As in Bethylidae, but the head is transverse, subquadrate or globose; antennae 
10-jointed; stigma large; fore tarsi of female chelate. 
Dryinus ormenidis Ashm. is parasitic on Ormenis pruinosa and 
O. septentrionalis, and the latter insect is also parasitized by Gonatopus 
typhlocybae Ashm. 
SCOLMDAE 
Females winged. Wings not folded longitudinally in repose; a constriction be- 
tween the first and second abdominal segments; legs of usual length; posterior femora 
when directed backward not reaching to middle of abdomen; sternellum large, sharply 
defined, extending between intermediate coxae; tibiae usually flattened with bristles 
exteriorly. 
