REPORT OF THE ENTOMOLOGIST. 301 



many are fomid witliin one insect. The cocoons of most species are 

 S})un within the body of tlie parasitized insect; but others, as in the 

 genus Bfierof/aster, emerge and spin their small, oval, often bright-colored 

 cocoon s on the outside. The family, as a whole, is one the members o 

 which are of immense service to agriculturists in destroying great 

 luunbe^s of noxious insects. 



The yellow-banded ichneumon {Phnpla conquisitor, Say). (Plate 

 XIII, fig. 5.) — This is one of the most numerous and most noticeable of 

 the parasites of the cotton-worm. It was first scientifically described 

 by Thomas Say, in 1835, who found it in Indiana. He described it un- 

 der the generic name of Gryptus, but it is now considered a Fimpla by 

 Mr. Cresson. The yellow-banded ichneumon was bred extensively from 

 the chrysalids of the last brood of cotton-woinns, and, so far as we are 

 aware, has never been bred from any preceding brood. 



That the earlier broods, if such exist, may be reared in other insects 

 is possible, from the fact that very many members of this family are not 

 confined to one species of insect, and from the fact that Say described 

 the original individuals as from Indiana; and it is probable from their 

 rarity, if not actual absence, among the earlier broods of cotton- worms. 



The length of time which it takes one of these parasites to undergo 

 its transformations has not been observed. If the larva spins a cocoon 

 at all, it is very slight; so slight, indeed, that upon breaking off the end 

 of the parsitized chrysalis the pupa of the i)arasite is exposed to view. 

 Tlie perfect insect emerges in late fall, in midwinter, and in. early spring, 

 through an irregular hole which it gnaws through the skin of the 

 chrysalis, usually near the head. 



The fact that these parasites are frequently alive within the chrysa- 

 lides throughout the whole winter has given rise to the supposition on 

 the i)airt of many that the chrysalis itself was still aUve, fi-om the mo- 

 tion imparted to it by the contained insect, and have thus been led to 

 believe implicitly in the hibernation of the cotton- worm in the chrysalis 

 state. Many chrysalids were sent to the department during the past 

 winter by persons holding this belief, but, without exception, those spec- 

 imens which still seemed to have Mfe conta.ined each the pupa of a yel- 

 low-banded ichneumon. 



The evidence given by Br. Gorham and Mr. Affleck, as well as our 

 own experience the past year, would seem to show that this parasite is, 

 during certain years, very abundant indeed upon the last brood of worms, 

 and although it might at first be said that the good accomplished by 

 them is smaller than if they were abundant with preceding broods, yet, 

 when we consider that every individual of the last brood which is para- 

 sitized redu(ies by just so much the imml)er of possible hibernators and 

 founders of families the succeeding spring, then we can appreciate the 

 amount of good which this parasite accomplishes, and although we may 

 not indorse the somewhat extravagant estimates of Dr. Gorham and 

 Mr. Affleck, still we may consider ourselves deeply indebted to the yel- 

 low-banded ichneumon. 



The ring-i^egged pevipla {Pimpla annuUpes, Br.). Plate XIII, fig. 

 4. — September 1, 1879, there issued fi-om a cotton-worm chrysalis one 

 specimen of the ichneumon to which Professor Eiley gave the above 

 popular name in his fifth Missouri Entomological Eeport. This is the 

 only specimen which has been bred this year. It is an old acquaintance, 

 having been bred from the walnut case-bearer (Acrohasis juglandis, Le 

 B.) by Dr. Le Baron, and from the codling moth of the apx)le {Carpo- 

 capsa pomonella) by Professor Eiley. It is a widely distributed species, 

 being found all over the country, north, south, east, and west, and that 



