Vol. xxx ] ENTOMOLOGICAL XF.XVS. 1.^3 



examine vegetation, bark and stumps of trer.-. heaps of dead 

 leaves, or whatever is found underneath stones ; he will oc- 

 casionally proceed to sifting, but in this case, of dry material. 

 He will not examine, as a rule, the wet soil adjoining water; 

 therefore he will take Tabanid larvae only occasionally. 



These larvae are, however, almost invariably present in the 

 soil immediately above water, at the edge of brooks, ponds, 

 lakes and streams, small springs and w r ater holes ; in short, 

 almost any kind of permanent body of water. They may be 



three different dips of the net and always at two or three feet distance 

 from shore. There was no possibility that they came from anywhere 

 but in or under the water. 



Tabanid larvae of various species have been taken by myself in the 

 mud of the edge, not submerged, in the months of September, October, 

 November and February when the weather was mild, but it is possible 

 that they are able to pass the cold periods of the winter below the 

 water since, according to my experience, they apparently do not stand 

 much freezing; on the other hand, their need of oxygen is not as great 

 in winter as in summer. That the very young stages of many species 

 (Chrysops^ undoubtedly live submerged, has already been stated; those 

 stages may derive oxygen from submerged plants (algae, etc.). 



I notice that H. H. King (Report Wellcome Tropical Research 

 Laboratory, Bulletin of Entomological Research, Vol. i. Part 4, De- 

 cember, 1910, page 265.) has stated of the larvae of the African 

 T. ditacniatus, that they were found submerged in a small water 

 channel, the water of which was overgrown with a covering of green 

 slime and if this was cleared away, a few larvae could generally be seen 

 at the surface. "On stirring the mud at the bottom and edges of the 

 water," says King, "more would appear, while if one waited for an 

 hour or so, specimens would continue to rise. They were apparently 

 living at the bottom of the pools and coming periodically to the surface 

 to breathe. They could be seen rising to the surface by a lashing 

 motion, and if left undisturbed would, after a few seconds, sink out of 

 sight again." 



Certain species of Tabanidae live, as larvae, under stones in shallow, 

 rapid-flowing water, notably T. kiiu/i (King) and 7'. riVd.r (I line). 

 The latter species may be taken if a sieve is held so that as a stone is 

 being lifted, the larvae under it are swept into the sieve by the current 

 (Hine). 



These exceptional cases should be taken into consideration by collec- 

 tors, but, on the whole, the rule holds i;ood that Tabanid larvae are 

 found in the soil and mud immediately above water and near the edjje, 

 as hundreds of captures have demonstrated. 



