766 M. W. R. de V. GRAHAM 



its biology. In 1905-6 and succeeding years large numbers of the parasite were 

 imported into Massachusetts and it soon spread over most of the area infested by 

 the brown-tail moth. In 1920 the satin moth, Stilpnotia salicis L., was discovered 

 in Massachusetts where it soon spread over a considerable area, and in 1926 the 

 Eupteromalus was found to be also attacking this species. In both cases its life 

 history is similar. The larvae of the Eupteromalus feed externally on the small 

 hibernating larvae of the hosts during the autumn, then when fully fed spend the 

 winter within the hibernation web of the hosts. Pupation occurs in the web in the 

 following spring, and adults emerge in May and early June. Females of this 

 overwintering generation may then attack the cocoons of some of the primary 

 parasites of the moths, such as Apanteles spp. and Meteorus versicolor Wesm. The 

 latter has two generations, both of which may be parasitized by the Eupteromalus. 

 There may be as many as two generations of the Eupteromalus in the year upon 

 primary parasites of the moth in spring, and up to three generations upon the moth 

 itself in the autumn. On the other hand there may be no reproduction upon the 

 primary parasites, and only one or two generations upon the moth in the autumn. 

 Under laboratory conditions some females lived for as long as four months ; if the 

 same holds good under natural conditions, then some females of the overwintering 

 generation would be able to parasitize the young larvae of the moths in autumn. 

 Usually only one Eupteromalus emerges from each moth larva, but sometimes two or 

 three. In one case seven Eupteromalus were observed to develop to maturity on a 

 single larva of Apanteles melanoscelus (Ratz.). Other details of the biology of this 

 Chalcid, including descriptions of the early stages, were given by Proper (1931). 



I am using the name chrysorrhoea (L.) for the brown-tail moth, a host of 

 Eupteromalus peregrinus sp. n., following Continental lepidopterists and the opinion 

 of Collenette (1947 : 259) who examined the syntypes of chrysorrhoea in the Linnean 

 collection. 



Kurdjumov (1912 : 228-229) noted considerable variation in the number of 

 teeth in the mandibles in the species which he identified as nidulans, some reared 

 from Euproctis chrysorrhoea ; most specimens had three teeth in the left mandible, 

 four in the right one, some four teeth in both mandibles, whilst one female had 

 five in both mandibles. I have not examined enough material of peregrinus sp. n. 

 to know whether the mandibles are variable. On the whole, however, the dental 

 formula in other species of this genus appears to be reasonably constant. 



Eupteromalus micropterus (Lindeman) 

 (Text-figs. 616, 642) 



Merisus intermedins var. microptera Lindeman, 1887 : 182, 6* $. 

 Baeotomus coxalis Ashmead, 1897 : 83, $ $. 

 Eupteromalus arvensis Kurdjumov, 1914 : 3-4, 6* ?• 

 Eupteromalus micropterus (Lindeman) Gahan, 1933 : 86—89, o* $• 

 Eupteromalus micropterus (Lindeman) ; Nikol'skaya, 1937 : 10-11, <J $. 



Type material (not seen). 



