OF CERTAIN CHALCIDIDÆ AND ICHNEUMONIDÆ. 67 
MONODONTOMERUS NITIDUS. 
On the 12th of September, 1847, I detected, in several cells of Anthophora retusa, in a 
dry clay-bank at Gravesend, a number of white Hymenopterous larvee, which at first I 
mistook for those just described. "There were from twelve to twenty-five in each cell, appa- 
rently full-grown, and measuring each about one quarter of an inch in length. "The body, 
in these larvee (fig. 7 & 8), was formed of fourteen distinct segments, each divided trans- 
versely on the dorsal surface into two, and covered with exceedingly fine, scattered, brown- 
ish hairs. The head was small, and provided, as in all parasitic Hymenoptera, with short, 
transverse, corneous mandibles, and the larvæ had considerable power of locomotion, by 
the extension and shortening of the segments. The whole of the food that had been pro- 
vided for the bee-larva was already consumed, and the bee-cell contained only the para- 
sites and the dried tegument and head of the young bee, which seemed to have been 
starved. It was a question with me whether the bee-larva had not been killed by the 
other larve piercing it, and abstracting its fluids from without? This query, then, 
seemed to be answered by the circumstance that the number of the parasites was dis- 
proportioned to the size of the victim, which, had it served as food for them, would in all 
probability have been entirely consumed. Besides which, one anatomical fact showed that 
they were external feeders,—their bodies were covered with a few scattered hairs, appre- 
ciators of contact; a condition which I have never yet observed in the soft-bodied, inter- 
nal-feeding larve of other Hymenoptera, and one which is as little required by them, as it 
doubtless would be inconvenient. Added to this, the great power of locomotion pos- 
sessed by these larvze,—which is neither possessed nor required by internal feeders, which 
remain almost constantly in the same spot,—suggested the opinion that it is on the food of 
the bee that these larvæ subsist, and not on the young bee itself, which may perish merely 
by deprivation of its proper nourishment. The larvæ also exhibited some indications of the 
formation of an anal outlet to the alimentary canal, which are not apparent in internal 
feeders at this stage of growth. 
I preserved these larvæ, in the cells in which they were found, through the following 
winter, and although the remains of the bee were left with them in the cell, it continued 
untouched, and they exhibited no further change until the middle of May 1848. At that 
time some of the specimens gave signs of approaching transformation, in the shortened 
and more shrivelled appearance of their bodies. Each of the larvæ then spun some very 
delicate silk, in small quantity. Shortly before they were ready to enter the nymph state, 
the alimentary organs became perforated, and fzeces were then passed for the first time 
during the whole period of the insect’s previous existence. The fzeces passed were little 
solid brown masses, that closely resembled the fzecal masses passed by the pollinivorous 
larva of Anthophora, which, like its parasites, as I have constantly found, passes nothing 
from its alimentary canal until it is about to change to a nymph. These fæcal masses 
seemed to indicate the supposed nature of the food,—pollen and honey ; and to support 
the opinion formed of the habits of these larvæ from. some points in their external anatomy. 
From twelve to twenty masses were passed by each larva : these were composed of the 
refuse of digestion and of epithelial cells accumulated during the period of feeding, and 
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