200 REPORT UPON COTTON INSECTS. 



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. This would undoubtedly 

 facilitate our knowledge of the number of broods. If the larva spins a 

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

 the end of the parasitized chrysalis the pupa of the parasite is exposed 

 to view. The 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 part of many that the chrysalis itself was still alive, from 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 chrysalides were sent to the department during the past 

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

 mens which still seemed to have life contained each the pupa of a yel- 

 low-banded ichneumon. We have already quoted from Mr. William 

 Jones's graphic description of an experience of this sort. Dr. Anderson 

 was deceived in the same way, and chrysalides which he had kept until 

 some time in December were shown by Mr. Schwarz to be parasitized. 



The evidence given by Dr. 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 everj' individual of the last brood which is parasi- 

 tized reduces by just so much the number of possible hiberuators 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. Gorhain and 

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

 low-banded ichneumons. 



THE RING-LEGGED PIMPLA (Pimpla annulipes, Br.}. September 1, 

 1879, there issued from a cotton-worm chrysalis one specimen of the 

 ichneumon to which Professor Riley 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 (Acrobasis juglandis, Le B.) by Dr. Le 

 Baron, and from the codling moth of the apple (Carpocapsa pomonella) 

 by Professor Riley. It is a widely distributed species, being found all 

 over the country, north, south, cast, and west, and that it is common is 

 shown from the fact that Professor Riley bred 20 females from a lot of 



