Ichneumon. HYMENOPTERA. 185 



Many apterous infe&s are found, which, 

 without doubt, belong to this genus •, thefe very 

 much refemble the apterous MutilU^ from 

 which they are diftinguifhed, when living, by the 

 continual vibration of their antennas, which mo- 

 tion is not obferved in the antennae of the Mu- 

 tillas, and after death, by the roundnefs of their 

 thorax, which is lefs retufe than that of the other 

 genus, and by their long and (lender abdomen, 

 which is likewife frequently joined to the tho- 

 rax by a petiolum. They are diftinguiihed 

 from the Sphex, which they likewife refemble, 

 by the number of articulations in their an- 

 tennas. 



Some of thefe apterous Ichneumons are, with- 

 out doubt, females, having the fting, through 

 which that fex depofit their eggs •, others of 

 them appear, from their being deprived of that 

 fting, to be males. Geoffroy however afferts, 

 that they are all females : perhaps that author 

 had only met with fuch as had (lings. 



The larvse of many Ichneumons not only 

 Jive, but likewife undergo their metamorphofis, 

 in the chryfalids or caterpillars of Lepidopte- 

 rous infe&s ; others of them, when arrived at 

 their full growth, pierce the (kins of their lodg- 

 ment, 



