308 NEW YORK STATE MUSEUM 



men, legs, etc. like Thalassomyia. The fore metatarsus is shorter 

 than its tibia, the fourth tarsal joint on all feet of both sexes 

 obcordate, shorter than the fifth; apex of each tibia with two 

 delicate setae; wing venation as in Thalassomyia, the surface 

 under a low power, appears punctate, under high power, short 

 haired. 



The larvae were found upon the rocks among the algae at the 

 seacoast, in the Bay of Saint Malo, Brittany. They are described 

 as green in color, ten or twelve mm. in length. The labiuni has 

 14 teeth, the two median, larger than those adjacent; in other 

 respects it does not appear to differ from Thalassomyia fusca. 

 The eggs are oval, measuring 200 to 280 microns, and are 

 deposited singly or in little groups, embedded in a jellylike 

 substance. 



The type species and the only one described, is S . i s e m e r i - 

 ni u s Chevrel. From Chevrel's description it will be seen that 

 the female differs from Thalassomyia fusca and c o n - 

 gregata in the form of the first and second palpal joint and 

 in color characters. Whether it differs in any particular from 

 T. frauenfeldi I am unable to say since Schiner's description does 

 not mention the form of the palpal joints. The male differs from 

 the male of T. fusca in the number of antenna! joints, the form 

 of the first two palpal joints and in the formation of the tarsal 

 claws. The males ofT. congregata and frauenfeldi 

 have not been described as far as I am aware. 



Genus 46. Macroptilum Becker 

 Mitteilungen d. Zool. Museum. Berlin No. 2. 2:77 

 Since the foregoing pages were written it was found that this 

 genus, which was recently described by Becker, was overlooked. 

 The type of the genus and the only described species is M a c r o p- 

 t i 1 u m n u d u m BeckeT, from Egypt. 



Errata 

 P. 142, line 14, for " pulcripennis " read " pulchripennis." 



