18 THE CANADIAN ENTOMOLOGIST. 



Stage V — Head without side line, colour dull pink, lines 

 yellowish, the dorsal narrow and alone continuous; tubercles 

 appear dim from being nearly concolorous, IV most prominent, 

 and I\'a always defined on joint ten. 



Stage VI — Very cylindric, paler, otherwise no change. 



Stage VII — Now more robust, tubercles conspicuous b>' reason 

 of the semi-translucence; IV'a has continued on ten, but has never 

 equalled IV. Length, 33, 39, 43 mm. July 15-Aug. 12. 



A chief parasite with the species is a Tachina fly, to which 

 attention has been previously called with other species, as being a 

 general check in the genus. ()ur reference to it as Ceromasia 

 myoidaa we learn through the kindness of Dr. C. H. T. Townsend 

 is in need of revision, and on this occasion we may deal with yet 

 another correction Our understanding of the matter is that the 

 above name refers to a European, or an assumed cosmopolitan 

 insect, but infercntially we would not expect such to be critically 

 involved in the economy of a large American genus, a genus so 

 thoroughly American that a selection of widely differing food- 

 plants in many cases exists with plant genera found only in America. 

 From our limited knowledge of the Hfe history, it appears this fly 

 may be associated only with Papaipema, or such similar boring 

 larva? as flourish at about the same date. Over-wintering puparia 

 do not gi\e up images until July, when the borers are of suflicient 

 size to answer their purpose. There appears to be two broods of 

 the flies, though it may be that those over-wintering are merely 

 tardy lar\a? in pupating, or possibly to having an unusually large 

 food supply. A fortnight's difference in pupation seems sufficient 

 to cause the later ones to overwinter. Ovi- or larviposition may" be 

 merely within the gallery opening, there being opportunity for 

 attachment to the host, as it has frequently to come to the orifice 

 to dispose of frass. Some of the Ichneumonidce have been en- 

 countered 20 cm. down in these galleries, but on such occasions it 

 was the pupa which was sought. While the fly larvae must subsist 

 internally, when about mature they may be found outside the 

 decaying shrunken host from which they move a slight distance 

 to pupate. The pupa is cylindric, with ends rounded, unattached 

 and unprotected in the gallery, colour brown. 



