24 "Entomology. 



ARTICLE III.— Entomology. No. I. By William Coup ee 



Toronto. 



In concluding my Notes on the Distribution of Insects, Vol. II. 

 p. 40, I promised to mate some remarks on insects injurious to 

 vegetation, more particularly the parasites that destroy the staff 

 of life, and concerning which so much has been written of late. 



Harris, one of the best English writers on American insects, in 

 his history of the Dipterous Order, must have been unacquainted 

 with the fact that many species of the two-winged flies pass 

 the winter in a semi-torpid state. In the month of January of 

 the present year, I discovered two species in society. One of 

 these, belonging to the genus Musca apparently a cuckoo-fly, 

 was found in an old decayed stump, that had originally been per- 

 forated by beetles of the genus Monohammus. Through the holes 

 thus made the flies reached the interior. They were found in 

 clusters of from thirty to forty ; each portion occupied a dry 

 crevice, and were in a semi-torpid state. I have placed two spe- 

 cimens in my cabinet, and a description will appear in another 

 paper. 



The other is a Cecidomyice. Its head, antennae, thorax, and 

 body are black; femorse whitish ; tibiae black ; wings have a blu- 

 ish colour, rounded at tip. Length \\ lin. These insects take 

 up their winter quarters in the stems of the Rubus villosus (a very 

 common fruit-bearing plant in Upper Canada), made tubular by 

 the larva of Saperda (Oberia) tripunctata having devoured the 

 pith during the month of June of the preceding year. They 

 occupied every stem examined, each containing about two hun- 

 dred specimens, huddled together in a semi-torpid state. In 

 many instances these insects enter holes made in the sides of the 

 plant by other insects ; in other examined specimens there were 

 no side entrances, but an opening on top, which to all appearance 

 had been originally the work of a Saparda or Cephus, as I found 

 the larva of the last genus devouring the pith immediately be- 

 neath the torpid Cecidomyice. 



Are they destructive insects ? If so, with nothing to obstruct 

 their exit, what can prevent their issuing forth in hundreds at 

 any favourable season to produce millions? It is therefore ad- 

 visable to destroy every medullary plant growing in the vicinity 

 of cultivated lands, as it is an unmistakeable truth that they pro- 

 tect many minute insects from moisture and cold. 



