igS Records of the Indian Museum. [Vol. XVI, 1918.] 



of their habit of accumulating debris on the short hairs which 

 cover the abdomen and caudal appendages so that it needs the 

 closest scrutiny to detect them. Quite occasionally protozoa such 

 as Vorticella are found adhering to their bodies. They are pure 

 rectal breathers, and if the larvae be viewed in muddy water, 

 strong currents of particles are seen issuing to and from the rectum. 

 It is reasonable to assume by analogy that the larvae of 

 Micromerus and the associated genus Rhinocypha are closely 

 similar in their morphology and if so, the above description will 

 confirm the opinion expressed by Dr. Laidlaw, that the two should 

 be placed together and raised to the rank of a subfamily. It will 

 be seen that no true, and certainly not functional, caudal gills are 

 present, these being replaced by caudal appendages which seem 

 only to serve for purposes of defence. The autotomy associated 

 with these appendages also points to their function as one of 

 defence only^ as if the insect be seized by any other, it merely 

 parts company with the appendage and makes its escape. A 

 similar habit probably exists in Rhinocyphine larvae and may 

 account for the absence of the caudal appendages in an incomplete 

 specimen described in a note by Dr. I^aidlaw. 



