27 



DESCRIPTION OF THE SPECIES. 



The female sawfly may be recognized with the aid of the accompany- 

 ing illustrations — figure 7, 0, representing the insect with wings 

 expanded and three times the natural size, figure 8, <?, showing the 

 same with wings folded and natural size, on a violet leaf — and Cresson's 

 translation of Provancher's description (Tr. Am. Ent. Soc, Yol. VIII, 

 p. 38): 



" 9 • — Length, 0.22 inch; black; head transverse, angular, as broad as the thorax, 

 punctured, with a furrow on each side behind the ocelli; antennae moderate; palpi, 

 tegulse, legs, with trochanters and tips of the cox?e, dull yellowish-white; posterior 

 femora except base, tips of their tibiae, with their tarsi, black or deep brown; 

 abdomen entirely black, short and stout; wings hyaline, nervures brown, the costa 

 and stigma deep brown. ' ' 



The flies reared at Wash- 

 ington differ slightly from 

 the above description, as did 

 those reared by Dr. Dyar, in 

 having the fore and middle 

 tarsi darker toward the 

 apex. Some of the veins and 

 stigma are very dark brown 

 and others are black. 



Measurement of the mate- 

 rial at hand gives an average 

 of 12.5 mm wing expanse and 

 6.5 mra total length of body. 



THE EGG AND OVIPOSITION? 





Fig. l.—Emphytus canadensis— a, female sawfly; b, larva; 

 c, abdominal segments of larva from above; d, pupa; e, 

 cocoon — all except c four times enlarged (original). 



The individual fly which 

 issued April 18 was placed 

 in a jar with a potted violet 

 plant, and was soon running 

 about on the leaves with 



vibrating antennae and active jaws and ligula, apparently feeding freely 

 and making frequent attempts to insert her ovipositor in the leaves. 

 This she was unable to accomplish with many of the older leaves, 

 nearly all of the eggs found having been inserted in the tenderer leaf- 

 age. Oviposition and the subsequent escape of the young larva from 

 the place of deposit is not unlike that of the common pear slug, Erio- 

 campoides limacina Retz., with the process reversed, the egg being- 

 inserted from the upper side of the leaf and the larva escaping on the 

 under surface. The ovipositor is thrust through from above to the 

 lower epidermis, which is left intact, the nidus thus formed with its 

 contained egg appearing as a blister on the lower surface. 



