igi3.] Miscellanea. 245 



8. Salpa zonaria (Pallas). 



Both generations have been found in the northern part of 

 the Andaman Sea and the solitary generation was found at station 

 393, in a mid-water net. 



The German deep-sea expedition on the ''Valdivia" visited 

 neighbouring waters, passing from Sumatra to the Nicobar Is., 

 and thence to Ceylon in February, 1899. In this region they did 

 not find C. baken, S. cylindrica, S. confoederata or S. multitnita- 

 culata. On the other hand , they obtained C. pinnata, C. affinis, 

 C. floridana, S. fustformis aspera, and S. amhoinensis. 



It appears therefore that much work remains to be done, 

 both in studying the forms that inhabit Indian waters and in 

 noticing the seasonal occurrence of particular species many of 

 which have an almost world-wide distribution. 



T. L. BOMFORD. 



INSECTS. 



Adaptation in the habits of a Tabanid Fly. — In Miss 

 Ricardo's description of the Tabanid Haematopota litoralis from 

 Puri in Orissa {Ann. Mag. Nat. Hist. (8), ii, p. 546, 191 it is 

 stated that the species is common on cactus hedges in the daytime. 

 The case is one of considerable interest from a biological point of 

 view and I have only waited for the publication of the description 

 to give the facts in full. In August, 1910, 1 found both sexes of the 

 fly abundant on a hedge of Prickly Pear [Opuntia elatior , Mill.) 

 running parallel to and some hundred yards distant from the sea. 

 In the heat of the day they sat quietly at the base of the bunches 

 of thorns scattered over the flattened and laterally expanded 

 stems of this cactus, and were easily captured by inserting a small 

 glass tube over them, except when, as was often the case, the 

 position of the thorns rendered this manoeuvre impossible. lyike 

 other Indian species of the genus, H. litoralis is as a rule matu- 

 tinal and crepuscular in habits, only becoming active in the 

 morning and evening. The other species with which I am 

 acquainted rest on rocks, walls or the bark of trees, on which 

 their mottled wings render them extremely inconspicuous. H. 

 litoralis is by no means inconspicuous on the green cactus stems, 

 for its colouration is not markedly different from that of its all es. 

 Its peculiar habits, moreover, expose it to another danger than 

 those which might arise, were it not protected by the thorns, 

 from being conspicuous ; for in the high winds that often prevail 

 on the east coast of India flies making their way on the wing to 

 the protection of tue thorns are liable to be impaled upon them. 

 This often occurs. Doubtless, however, the advantage gained 

 from the adoption of the habit is greater than its inherent risk, 

 for it would be very difficult for any enemy, except of course a 

 microscopic one, to attack the fly at the base of the thorns. The 

 most interesting feature of the case lies in the fact that the habit 

 must have been adopted recently, for Opuntia elatior was only 



