83 



in conjunction with this Root-louse, though he had failed to breed 

 it," and which he there describes as "a footless maggot five or six 

 times as large as the Root-louse, and of a dirty yellow color, attenuated 

 at both ends, the head being quite retractile;" and which he after- 

 wards pronounces to be "clouljtless the larva of a C ecidomyia, the same 

 Family to which the Hessian Fly belongs/' and to "take some part, 

 probably, in inducing the deformities of the roots." But certainly 

 the insect that I showed to Mr. Riley does not even belong to the 

 same great group of the Two-winged Flies as the Gall-gnats {Cecid- 

 omyici,) inasmuch as it has what is called a "coarctate" pupa; (see 

 above p. 39;) and I feel pretty confident that it will prove to be 

 the Cannibal appointed by Nature to prey upon these unruly root- 

 feeders, and keep them within reasonable bounds. The Syrphus 

 family, however, to which it apparently belongs, includes many genera, 

 which, in the preparatory states, can scarcely be distinguished from 

 each other, and some of which feed upon decaying animal and vege- 

 table substances, (Xylola, etc.,) while others (Syrphus, 8cceva, Volu- 

 cella, etc.,) are Cannibals and feed upon other insects. In any 

 case I hope before next summer is over, to solve the mysterj 

 definitively, by rearing the winged Fly from the pupa which I found. 

 If, as I confidently anticipate, it should prove to belong to one of the 

 Cannibal genera of the Syrphus family, the reason why Mr. Riley 

 failed to breed it becomes manifest at once. He supposed it to feed 

 upon vegetable matter, and therefore his specimens, being, in all prob- 

 ability, not supplied with a due allowance of their natural diet — the 

 Root-lice — perished of starvation. Such accidents often happen to 

 the most experienced breeders of larvaa; and, moreover, almost all 

 Cannibal larvte are much harder to breed than plant-feeding larvae. 



In quoting what I believe to be a mistake made by Mr. Riley in 

 regard to the above larva, I intend no disrespect whatever to that in- 

 dustrious and intelligent entomologist. There is not an entomologist, 

 living or dead, in any country of the known world, who has not, at 

 one time or another, made such mistakes; and I am not ashamed to 

 confess, that I have repeatedly myself blundered in the same manner. 

 For example, I once took the dead and dried-up larva of a small Gall- 

 gnat (Cecidomyia) for the larva of a Gall-Fly (Cynips;) but, as soon 

 as I discovered my error, I embraced the earliest opportunity of 

 acknowledging it in print. And here lies the difference between the 

 men that write for victory and the men that write for truth. The lat- 

 ter frankly confess their errors as soon as they become aware of them ; 

 the former claim to be infallible, and never will allow that they have 

 been in the wrong. I could name an entomologist of deservedly high 



