198 THE CANADIAN ENTOMOLOGIST. 



Ent., Vol. XXIV. p. 137) upon the occupants of similar galls from 



Manitoba, I afterwards collected a pocketful. They were very much 



larger than those which are found at Ottawa, and perhaps scarcely so 



spherical. Many were evidently already vacated by the producing flies, 



but I hoped that they might still have other tenants. About a week 



later, as only three flies had emerged, I opened about half of them, and 



was rewarded by finding several inhabitants. The majority of the galls 



contained in the central cavity the empty puparium of the fly, but in 



several the larva of the fly had apparently not hatched or had soon after 



perished, as there was no cavity. In only one gall was found the pupa of 



Euryioma gigantea, and in this cavity there was no puparium of the fly. 



In winding tunnels in the pithy substance of other galls were found a 



Mordellid larva and pupa, which were placed in alcohol, and a few small 



Chalcidid pupae, one of which was evidently a smaller species of 



Eurytoma. Several dead larvte of the beetles were also found in their 



burrows. On June 21st, as nothing had since emerged, I opened the 



remaining galls, and in two I found living examples of Mordellistena 



nigricans^ Melsh. In each instance the central cavity of the gall 



contained the empty puparium of the Eurosta, which had escaped by its 



own exit, while the beetle was at the end of a long burrow through the 



solid pithy substance, and just cutting its way out. It is evident, 



therefore, that Mr. Brodie was mistaken in announcing this beetle as a 



true parasite of the fly, and as " bred from an Eurosta pupa-case." It 



is certainly only an inquiline, the larvge boring in and living upon the 



pithy substance of the gall. Some years previously (Can. Ent., Vol. 



XIII., p. 173) the late Mr. V. T. Chambers had recorded a Mordella 



larva (perhaps this same species) as " common in the galls of Gelechia 



gallce-solidagi?iis, Riley, in stems of Solidago, eating into and through the 



walls of the galls, but not disturbing the larvte or pupte of the moth." 



Besides the two beetles, there were found in the galls, in the small burrows 



made by the beetle larvte, three or four more of the chalcidid pupa? and 



two flimsy braconid cocoons, from which emerged specimens of Sigalphus, 



answering very well to the description of S. texanus, Cress. The small 



Eurytoma proved apparently to be E. sttidiosa. Say, while the remaining 



seven puptX developed into a species of chalcidid which I have not been 



able to determine. The latter species, the E. studiosa, and the Sigalphus 



are evidently parasites, not of the gall producing Eurosta, but of the 



inquilinous Mordellistena. We have, therefore, from these few galls 



examples of the fly which produces it, a true parasite thereon, an 



inquilinous beetle, and three parasites thereof. 



J 



