194 



gins of the concavity, and its rim is surrounded by long sparse bristles. 

 Studied under the liigli power of the microscope the face is seen to 

 be furnished with sparse short hairs each arising from a slight tubercle. 

 In younger individuals the surface is very faintly pubescent. There is 

 nothing in its intimate structure to suggest a sucking disc and it is 

 probable that Dr. Bergroth's inference that it might be such an organ is 

 incorrect. It should be stated that at the time Dr. Bergroth made this 

 suggestion we knew only this sex and the very fact that the female does 

 not possess it goes to prove that it is not developed for the purpose 

 of enabling the insect to cling to stones in swift currents as was hinted. 

 It is undoubtedly a secondary sexual character and unless it possesses 

 some important office in the act of coition it will be difficult to surmise 

 its raison d'etre. There is a possibility that its function is sensory, 

 but we have not had the opportunity to study its nerve supply. 



At our request Mr. Heidemann has prepared the following account 

 of his observations upon the habits of the species : 



"This interesting bug lives in clear running waters, and seems to 

 prefer points where the bed of the stream is rocky. I was unable to 

 find specimens at any other point on the canal, except at one very 

 rocky spot. I found the insects skimming over the surface of the water 

 in considerable numbers and in the same lively manner as do the insects 

 of the allied genera Metrobates and Stephania. They were very shy 

 and dived quickly beneath the surface when approached, and were 

 therefore difficult to capture. On the sides of the canal where there 

 was only a little ripple on the water I saw them more active immediately 

 above stones covered with slimy mud. I also noticed a few specimens 

 of Stephania in company with them. I captured with my net specimens 

 in all stages of development, from the young larva up to the full grown 

 adult. It is my opinion that there is more than one brood during the 

 year, since on the 4th of June I captured a single larva on the same 

 spot. I did not, however, at that time recognize its true affinities.'' 



EXTRACTS FROM CORRESPONDENCE. 



Further Notes on the Japanese Gypsy Moth and its Parasites. 



I read with, interest the report of the meeting of the Gypsy Moth Commission, 

 which appeared in Insect Lip^e, vol. hi (p. 368). 



I have had hut one poor specimen of Ocneria dispar to compare my specimen with, 

 but having heard that dispar was in Yezo, and as the appearance and habits are so 

 nearly identical, I took it for granted that it was Ocneria dispar without careful ex- 

 amination. 



Your statement that Ocneria japonica is somewhat larger than dispar is not con- 

 clusive to my mind that the two are not identical. We have specimens of Pieris 

 rupee that reach a maximum of two inches and three-quarters, and Papilio machaon 



