affect infj the Corn- Cropa. 
409 
Family Ichneumonides adsciti or ALVsiiDyE, the Genus 
SiGALPHUs, and have been named by Nees ab Esenbeck.* 
16. S. caudatus, from the length of the tail (fig. 39). — II is 
black and shining, indistinctly punctured ; the head is subglobose, 
wit h two lateral eyes, and three minute ocelli on the crown ; the 
antenna? are as long as the body, flail-shaped, slender and fili- 
form, composed of twenty or twenty-one joints, basal one the 
longest ; thorax oval and gibbose, the sutures very deep ; abdomen 
broader than the thorax, and rather longer, elliptic-ovate, witli 
three equal segments, the two first and the base of the third finely 
striated longitudinally ; the apex polished ; belly concave ; ovi- 
positor exserted, and longer than the animal, composed of an ovi- 
duct and two sheaths; wings four, transparent, iridescent; mar- 
ginal cell ovate, submarginal subovate; discoidal cells two, superior 
the largest, rhomboidal, inferior oblong ; nervures piceous, as well 
as the stigma, which is large and elongate-ovate ; legs pitchy, 
anterior ferruginous, excepting the base of the thighs and the 
tarsi, base of the other tibiae ferruginous : length from 4 to 1 line, 
without the ovipositor; expanse 1^ to 2^. (Fig. 40, the female, 
magnified.) 
As Dr. Herpin seems to have ascertained the economy of this 
parasite, or a closely-allied species, during its early stages, I shall 
transcribe his sensible observations : — " An Ichneumon, of which 
the female is armed with a long ovipositor, perforates the shell of 
the Chlorops egg, and deposits there its own. The yoimg larva 
of the Chlorops of the wheat grows and increases, although it en- 
closes in its body a mortal enemy. The larva of the parasite 
grows and flourishes with its victim, and she nourishes herself with 
its fatty substance ; but, how admirable ! the parasite never attacks 
any of the essential organs of life in the Chlorops, for if this hap- 
pened to perish, the parasite would infallibly die with it. After 
the diseased Chlorops has metamorphosed to a chrysalis, the para- 
site finishes by destroying it entirely ; and one sees with surprise 
an insect come out of the pupa of the Chlorops, not the destructive 
fly of the wheat, but an Ichneumon, which in its turn proceeds again 
to persecute the progenitor of the corn-destroying Chlorops." 
Having now completed the history of the instruments provided 
by Providence to check the ravages of the Chlorops, we will turn 
to those means suggested by the experience of man; and here 
again I shall translate a portion of Dr. Herpin's Memoir : — 
" In the years when the Chlorops exists in great quantities, the 
means to destroy it consist in pulling up, carrying away, and 
burning the plants which are attacked by them, as well of the first 
as the second laying. 
♦ Hymenop. Ichn. affin. Mon,, vol. i. p. 268. 
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