228 PARASITES OF GIPSY AND BROWN-TAIL MOTHS. 



even presuming that T. larvarum should not be established, but the 

 chances are not particularly in favor of such an outcome. It has 

 not been so long nor so satisfactorily colonized, and there is yet a 

 chance that it will be recovered as a result of the colonies which have 

 been planted, or which are likely to be planted in the future. No 

 especial attempt will be made to test its ability to exist as a race apart 

 from T. mella, but it is expected that its puparia will be imported in 

 some numbers in 1911 or in 1912, in connection with work involving 

 the importation of other Japanese parasites. 



TRICHOLYGA GRANDIS ZETT. 



Although generically distinct from Tachina, according to the at 

 present accepted and as is increasingly evident artificial classification 

 of the Tachinidse, Tricholyga grandis is so similar to Tachina mella 

 and T. larvarum as sometimes to be separated with difficulty from 

 those species. In Europe Tachina and Tricholyga attack the gipsy 

 moth with nearly equal freedom, but relatively a very few Tricholyga 

 have been reared from the brown-tail moth. The fact that Tachina 

 and Tricholyga do not usually occur in the same locality the same 

 year has already been the subject of comment. If may be that a 

 careful review of the rearing records of the two will show that 

 Tricholyga is increasingly important as a parasite in the more south- 

 erly localities, but such review has not been made with this point in 

 view. 



It was not until 1909 that it was definitely separated from Tachina 

 in the records of the rearing and liberation of the tachinid parasites, 

 and up to 1908 the two species were so inextricably mixed as to make 

 it very difficult to state with any approach to accuracy the relative 

 proportions of the two among the number colonized. There was 

 only a single specimen of Tricholyga among the several Tachina which 

 were preserved for museum specimens from among those imported 

 in 1906 and 1907, and on this account it is probable that Tachina was 

 in the considerable majority. 



In habits Tricholyga differs from Tachina in only a single con- 

 spicuous respect. It deposits the same sort of eggs, similarly placed; 

 its larvas appear to have the same feeding habits, and about the same 

 length of life cycle; but unlike Tachina it seems habitually rather 

 than occasionally to pupate within the caterpillar skin or pupal shell 

 of its victim. On this account some of its puparia have been diffi- 

 cult to find in the boxes of imported caterpillars, and it has been 

 found advisable when they are present at all, to keep the dead cater- 

 pillars inclosed until such flies as are present have emerged. 



Like Tachina, it probably hibernates in the puparium, but neither 

 of the two has ever attempted to hibernate when reared from im- 

 ported European gipsy-moth caterpillars. The introduction and 



