a 
XXXV1l1 
An interesting account of the habits and metamorphoses of a 
new species of Sitaris (S. Colletes), parasitic, as its name implies, 
on a species of Colletes (C. succincta, L.), has been given by M. 
Valéry Mayet in the ‘ Annales’ of the French Kntomological 
Society (Ser. 5, tome v., 1875), with two plates exhibiting the 
various stages of both these insects, from larva to imago; and of 
Epeolus tristis, Sm., obtained from the cells of this Colletes. 
The primitive larva of the aforesaid Sitaris, as carefully de- 
scribed and delineated in this memoir, is furnished with triwngui- 
culate tarsal claws, like that of Meloé; whereas, in M. Fabre’s 
remarkable life-history of Sitaris humeralis, the tarsi of the 
latter, in this stage, are represented as terminating in a single 
powerful claw (un ongle puissant, long, aigu, et tres mobile).* 
The young larva of 8. Colletes is supplied with a caudal 
apparatus (appareil fixateur, V. M.), consisting of two upeurved 
spiked appendages attached to the base of the eighth abdominal 
segment on the dorsal region, having a simultaneous action up 
and down, between which are two tubular processes emanating 
from a superincumbent plate and directed backwards, from whence 
filaments issue from time to time when the larva desires to affix 
itself to a hair of the bee or other object. Fabre, however, 
appears to consider such filaments, in the larva of S. humeralis, 
as ordinary caudal sete, which he describes as attached to the 
exterior margin of the ninth abdominal segment (l. ¢., p. 310). 
The Colletes-eg¢ is readily accessible to the young Sitaris, not 
being deposited by the bee, as in the cells of Anthophora, upon 
the honey-store itself, but affixed above this to the wall of the cell, 
whereby the difficulty and danger to be incurred in reaching the 
same, and the necessity of effecting this manceuvre at the moment 
of oviposition, are avoided. 
As this Colletes constructs her cells and deposits her eggs 
in the autumn, the Sitaris-larve, soon after their birth, attach 
themselves to their victims, instead of remaining, like those of | 
S. humeralis, seven months fasting in suspense, from the end of — 
September to the end of April, waiting for the Anthophore to 
emerge from their hybernacula. 
When more than one of these larvee occupy the same cell of the 
Colletes, they fight with great ferocity until one alone remains, 
the others being killed and thrown into the honey ; although it not | 
* Ann. Se. Nat., 4e Ser. (Zool.), tome vii., 1857, p. 310; pl. 17, fig. 2. 
