SOME ARTHROSTRACA FROM ST. KILDA 221 



I was interested to find among the large numbers of 

 specimens of Forficula auricularia, L., which occur on the 

 island, a number of the " high-males," the forceps of some 

 of the specimens measuring .75 cms., while those of the 

 "low-males" measured .3 cms. 



COELENTERATA. 



A few Hydroids were found on the rocks in Village Bay ; the 

 following species occur : 



Clava sqtmmata, O. F. Miiller. This was common. 



Coryne pusilla, Gartner. My friend Mr. F. H. Gravely, to whom I 

 showed these Hydroids, tells me that the specimens of this 

 species were remarkably stunted, having the hydrocauli very 

 much tangled ; the perisarc also was less regularly annulated 

 than is usual. 



Campanularia flexnosa, Hincks. 



THE UNIVERSITY, MANCHESTER, August 1907. 



HYMENOPTEROLOGICAL NOTES. 



By P. CAMERON. 

 I. NOCTURNAL HYMENOPTERA. 



THE Hymenoptera are, as regards the vast majority of the 

 species, light- and sun-loving insects. There are, however, 

 a few forms which are more or less nocturnal in their habits. 

 I am not now alluding to humble-bees (Bombi), which, during 

 warm and moonlight nights, may be seen actively collecting 

 honey or pollen, but to various species and even genera 

 of different tribes and families which apparently, to their 

 more or less nocturnal habits, have acquired a close identity 

 in coloration, as well as a peculiarity in their simple (ocelli) 

 and compound eyes. There may, of course, be exceptions, 

 but as a rule nocturnal Hymenoptera have their bodies of a 

 uniform fulvous or light brownish coloration, only slightly, 

 in some cases, marked with black. They have also their 

 eyes larger than is the case with most day-flying species ; 

 and, further, they approximate more to each other on the 



