166 ENTOMOLOGICAL SOCIETY 



half of this number can do to a full-grown tree, if their ravages 

 are not speedily intercepted, can be imagined, especially if the 

 fact is kept in mind that they attain the respectable size of 5 to 

 10 centimeters in length, and that their appetite, like that of 

 most other caterpillars, is altogether monstrous. 



A bearing cocoanut tree will thus be stripped of every inch 

 of foliage in a few nights and receive such a severe check in 

 its growth that, even with all due care in preventing the re- 

 appearance of the pest in the following years, at least two or 

 three crops will be lost. It is no rare occurrence, however, 

 that a tree will die outright, or become so weak that it can not 

 resist fungous and other diseases, and will gradually perish. 



After reaching maturity, or when the supply of food gives 

 out, the larva passes into the chrysalis stage, in which it re- 

 mains 12 to 1 6 days, and this is the time when the larva of an 

 apparently dipterous insect helps in the destruction of the 

 Brassolis. 



I have not been able to find out whether the mature parasite 

 deposits its eggs cutaneously into the caterpillar, or into the 

 chrysalis, or whether its ova are introduced into the alimentary 

 tract of the larva with its food, as I have found the parasite 

 larva only in the chrysalides. Doctor Darling, Chief of the 

 Board of Health Laboratory at Ancon, had examined almost 

 mature larvae of the Brassolis under a high-power microscope 

 without finding any traces of parasite ova in either the skin or 

 intestinal ducts. However, as only a small number of them 

 could be thus examined, on account of lack of time, it is possi- 

 ble that the few specimens under observation were not para- 

 sitized. As the parasite larvae are not protected with a skin 

 which, in my judgment, would be tough enough to withstand 

 the gastric juices of their host, the probability of a cutaneous 

 infestation suggests itself. 



The destruction of the Brassolis through its parasite seems 

 to be rapid, although the actual time required can not be given, 

 as those in captivity appeared to be free from infestation. 



From the microscopic examination of the contents of three 

 diseased and dead chrysalides by Doctor Darling, the following 

 points were learned: The contents were fluid and granular, 

 and a fresh smear showed many fat droplets, discrete and in 

 round aggregations (mulberry-like). The tracheal tubes were 

 found in some brown debris, but no parasite ova, bacteria, 

 or micro-organisms of any kind could be detected. With the 

 polarizing microscope the fat droplets did not show crosses. 



The fat droplets take the stain well with Sudan III. Stained 

 with polychrome methylene blue, there are numerous eosin 



