110 THE CANADIAN ENTOMOLOGIST. 



easily discovered. [Considered to be merely a variety of P. lucublandus by 



LeConte.] 



50. P(ECilus [Pterostichus] chalcites, Say. — Only a single specimen 



taken. 



[Not uncommon in Canada; for description vide Say's Ent. "Works, 



ii. 479.1 



ON THE ECONOMY OF A SPECIES OF FEONUS. 



BY WM. COUPER, Montreal. 



On the 8th of January last, while searching for bybernating Coleoptera in 

 the woods near Ottawa, I had occasion to strip the bark of a decayed ash 

 tree, under which, among other insect store, I found a small transparent and 

 curiously formed cocoon containing a larva of a fly which was at that time 

 unknown to me. The cocoon was imbedded in the bark, occupying what I 

 am now led to believe the excavation made by a grub of Czrambyx, or 

 some other Coleopterous bark-borer. When cocoons belonging to the genera 

 Evaniidje or Iciinetjmonidae are found under bark of trees, or stones 

 imbedded in the earth, we may safely assume that they are accompanied by 

 parasites, and that the original possessor has been devoured because it 

 was just the food that suited them. Thus it is not difficult to trace the 

 economy of many species of the above named genera ; but as I am not cer- 

 tain that either cocoon or insect were hitherto described, I have taken the 

 trouble to send you the following. The shape of the cocoon is oblong, sur- 

 rounded by a band, and covered by a thin pellucid lid, and the form resem- 

 bles a small coffin. The head of the insect was placed at the small end, and 

 the space in front of it is packed with minute particles of dust, evidently 

 produced from the bark by the original occupier. Length of cocoon 

 3-8ths inch. 



Feonus Area, n. sp. — Head black, glossy, impunctured ; eyes black, round ; 

 antennae black, two-eighths of an inch long ; thorax not so black as head ; 

 the sides beneath and between the wings dark chestnut, interspersed with 

 short fulvous hairs ; wings fuliginous; nervures and stigma black ; legs black, 

 hairy ; base of the femora fulvous ; abdomen bright red, with scattered 

 fulvous hairs; ovipositor black, as long as antennae. Length 3-8ths inch. 



I have another cocoon of the same form in my collection, but the work of 

 a larger species, being half an inch long. It therefore behoves that persons 

 who wish to study the economy of these useful insects, should search for 

 them early in autumn, when they will be discovered either destroying the 

 larva or funning the cocoon in which they rest during the winter. 



