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Vol. XLI. 



GUELPH, OCTOBER, 1909. 



No. 10. 



NOTES ON THE LARVA AND PUPA OF STHENOPIS 



THULE, STRECKER. 



BY J. M. SWAINE, MACDONALD COLLEGE, P. Q. 



Larvae and pupae of this interesting species were found in a willow 

 swamp near Macdonald College by Mr. G. Chagnon, Mr. W. Brittain and 

 myself on June 29th, 1909. They were taken from the bases of the stems 

 of the common swamp willow, Salix petiolaris, Smith. 



So far as we know, the mature larva and pupa have not been 

 previously described. 



Description of a nearly-mature larva : Length (alcoholic specimen), 

 70 mm.; diameter at second abdominal segment, 9 mm.; width of head, 

 5 mm. The shape is nearly cylindrical, the thorax is slightly humped, and 

 the last two abdominal segments are somewhat retracted ventrally. The 

 colour is white or yellowish-white with yellow, chitinized thoracic areas 

 and with small yellow-chitinized spots, from which arise the setae. The 

 setae are sparse, dark brown, and longer and stouter on the last two abdo- 

 minal segments. The body segments are much folded transversely, with 

 a strong lateral fold on each side. 



The spiracles are black, distinct, and situated on the first thoracic 

 and first eight abdominal segments. 



The abdominal feet are stout, situated on the third, fourth, fifth, sixth 

 and last abdominal segments. 



The head is reddish-brown, darker cephalad ; with the labrum, man- 

 dibles and palpi black ; irregular furrows radiate from the sparse, setigerous 

 punctures. The spinneret is slender, straight, and usually held at right 

 angles to the body, though capable of being retracted flat against the 

 ventral wall of the head. The ocelli are six in number, and are arranged 

 in two more or less distinct rows. 



The yellowish-brown cervical shield covers the dorsum of the first 

 thoracic segment between the spiracles. Above the spiracles on either 

 side is a slightly-curved, elongate, brownish-black, impressed marking, 

 bearing a black setigerous puncture at either end and one cephalad of the 

 middle. 



