1304 THE BUTTERFLIES OF NEW ENGLAND. 



To Mi?8 C. Guild, of Walpole, Mass., is due the sole credit of first 

 bringing to light, in 1809, an interesting egg parasite ( Trichogramma 

 minutissimum) , the first one which had then been known to me to attack the 

 eggs of our butterflies. By her cai'cful and patient examination of the leaves 

 of young birch trees, slic found a number of eggs, and among them five or 

 six which had been attacked by this parasite ; they could be instantly recog- 

 nized, because they had all turned of an inky black color. From the first 

 egg some specimens were probably lost. They made their appearance the 

 last of June, and eighteen specimens were obtained. Subsequently Miss 

 Guild brought me five more eggs, which had been enclosed in a tight box 

 and in which the specimens were all dead. Miss Guild thought that none 

 had escaped, and I counted seventy-nine specimens (nine male, seventy 

 female), making an average of sixteen to each egg. The parasites 

 escaped by eating their way out of a minute, nearly circular hole in the 

 aide of the egg, measuring .25 mm. in diameter. 



It has also long been known that the caterpillar is stung by Trogus 

 exesorius (88:3), the perfect insect finally escaping from the side of the 

 upper half of the chrysalis ; Mr. E. Norton of Farmington, Conn., has 

 also bred another hymenopterous parasite, Copidosoma turni (89 : 5) . Mr. 

 Riley's notes state that in 1871 he had bred two kinds of parasites from 

 the pupa ; and some chrysalids I obtained at Moosehead Lake, in Maine, 

 gave me a dipterous parasite, Mascicera frenchii (89:23). 



Desiderata. The distribution of this insect in Florida and Mexico, 

 Newfoundland and Hudson Bay, Alaska and northwestern America 

 needs to be better known before its exact limits can be defined. Our 

 knowledo-e of the districts within which the species is double brooded and 

 only double brooded is exceedingly scanty and vague ; very likely its digo- 

 neutism shifts to polygoneutism where dimorphism appears in the female, 

 but that is a question still open to investigation. Are there more than 

 three broods in the extreme south? Where the dimorphism obtains, the 

 ratio of the two forms (omitting the males) should be carefully deter- 

 mined for many different localities, to help determine its cause. Where 

 not monogoneutic, the relative number of chrysalids of the early broods 

 which prematurely hibernate should likewise be determined for many dif- 

 ferent localities. Probably the list of food plants could be considerably 

 extended. Is the buttei-fly, so conspicuously striped, in any way protected 

 by odor or nauseousness, and is the dark form of the female less subject to 

 attack than the striped? 



LIST OF ILLUSTBATIONS.-JASONIABES GLAUCUS. 



General. PI. 89, fig. 23. Mascicera frenchii, a dipterous 

 PI. 26, fig. 8. Distribution in Nortli Amer- parasite. 



ica. Egff. 



88:3. Trogus exesorius, a parasite. PI. 66, fig. 1. Outline. 

 89 : 5. Copidosoma turni, a parasite. 68 : 18. Micropyle. 



