17H (JVISV AM) BROWX-TAIL MOTHS. [Jan. 



rearing of a species of the genus M, h urns from the imported brown-tail 

 moth nests. From the larger larva? a second generation was reared after 

 a very brief interval, the cocoons appearing in about ten days in cages 

 in which the adult parasites were confined with their host insects. 

 This indicates a very short breeding period during the summer time, 

 and. although this parasite has not liecn reared in great numbers, its 

 quick breeding indicates that it is a very desirable introduction. Wliat 

 is probably the same species was occasionally found in boxes in which 

 the nearly mature brown-tail caterpillars were shipped, and a few 

 emerged from some of these caterpillars, which arrived alive and in 

 apparently a healthy condition. After the parasite emerged the larger 

 caterpillars seem not to have been fatally affected, but all have died 

 after transforming. The encouraging part of this introduction, aside 

 from the quick-breeding habits, is our knowledge that a native species 

 has been known to destroy 90 per cent, of the larva' of a native moth 

 infesting the western pines. 



The egg parasites this year have been reared in considerable num- 

 bers from the brown-tail moth eggs, in lesser number from gypsy moth 

 egg-s. Two species have been reared and have been carried through 

 several generations in artificially retarded egg masses. One is a Procto- 

 Irypid of the genus Telcnomus, and the other a Chalcid ol' the genus 

 Trichogramma. 



In addition to the sending of brown-tail hibernating nests above 

 referred to. dmini: the fiscal year ending June 30, 1907, there was re- 

 ceived from Europe a total of 1,375 boxes, containing the matured 

 caterpillars and pupa? of the gypsy moth and the brown-tail moth. Of 

 these, S72 boxes of the brown-tail were received during June, 1907, and 

 82 of the brown-tail and 425 of the gypsy during July and August, 1906. 

 The percentage of parasitism varies considerably, according to the 

 different localities from which the nests were sent, but it must be re- 

 membered that in these European localities the percentage of para- 

 sitism is constantly lluctuating, being smaller in some years and almost 

 c.xtenninative in others. A part of the parasites sent over do not 

 emerge from the caterpillars or pupa- until after they arrive at the 

 laboratory; others are found in the boxes iii the pupal condition; and 

 a few. especially toward the latter part of the season of sending, trans- 

 form into adults and die on the journey. 



Of these parasites, about DO per cent, have been Tadiinid flies, and 



perhaps 12 species ha\e 1 u reared from the two host insects, most of 



them he in- common enemies of both species. About 40 per cent, of 

 these Hies emepje :i s adults at nearly the time of the emergence of the 

 moths of the species which they attack, while the remainder pass the 

 winter in the pupal condition, emer-in- the following spring. Seven- 

 teen hundred adult Tadiinids were col,,ni/ed in July and Auuusl. 190P>, 

 and more than 2.000 diirimr .lime. l!!(7. It is now obvious that a very 

 lar-e number will be on hand hibernating during the winter of 1!M>7 OS, 



