on various Species of Hymenopterous Insects. 135 
and the repeated opportunities offered by rearing the latter insects, 
as is so commonly practised abroad, and which have never hitherto 
afforded a case in support of such parasitism,—the totally different 
localities of the insects in question, the Uroceride inhabiting fir 
districts, and the Papiliones moist districts, where their favourite 
food occurs,—the many instances on record of the Uroceride being 
found in the larva state in the body of trees, where of course they 
could not be parasitic upon the external feeding larvee of the two 
species of Papilio in question,—the impossibility of these Jarvee 
being at one time internally parasitic on the larvee of the Papi- 
liones (as must have been the case with Signor Franchi’s specimen), 
and externally parasitic on Xylophagous larve, feeding in the 
interior of trees, (like that of Scolia, observed by M. Passerini, 
which has also been assumed to be the case with the Urocerous 
larva,)— and lastly, but by no means of least importance, the 
structure of the mouth of the larve of the Uroceride, excellently 
adapted, from the formation of the mandibles, for feeding upon 
solid wood, but quite unlike those of any parasitic Hymenopterous 
larva,—are all circumstances which seem sufficiently to disprove 
the conclusion that ‘‘le larve dei Sireci sono zoofaghe.” 
The genus Cephus, Latr. (T'rachelus, Jur.; Astatus, Klug,) in 
various respects is one of great importance in regard to the rela- 
tionships of the insects before us ; and since the preceding memoir 
was written, several valuable observations have been made on its 
preparatory states, which throw considerable light upon its affini- 
ties, a circumstance of no little importance, when it is remembered 
that it has been arranged by the three great Entomologists, Leach, 
Klug, and Latreille, in as many different families, namely, the X7- 
phydriade, Siricide, and Tenthredinide. 
The larva of C. abdominalis was observed by the late M. 
Audouin to be produced from eggs deposited in a spiral direction 
round the young shoots of the pear, the larva feeding mithin the 
slender shoots, and being fleshy, with six minute thoracic legs, but 
destitute of prolegs, and with the terminal segment of the abdo- 
men attenuated, and terminated by two very minute points ; there 
is also a minute conical lobe, near the base, on each side of this 
segment. This memoir has not yet been published. 
A memoir on Cephus pygmeus was however published by MM. 
Dugaigneau and De Tristan, in the Memoirs of the Société des 
Sciences, &c. d’Orleans, vol. i., in which the injuries committed 
by this insect upon the rye crops in France were detailed, and the 
insect described ; and M. Dagonet, in a series of observations made 
in 1839 and 1840, published at Chalons in 1840 and 1841, has also 
