THE CANADIAN ENTOMOLOGIST. 27 



It is bordering the habitat of C. lecontei but nearer the 

 drifting sand, that we meet with the finest of all our tiger beetles, 

 a large strong-flying insect which will often travel three hundred 

 feet or more at a stretch. This is C. manitoha Leng., next 

 to limbata, the commonest on the sand. He is a great terror to 

 ants and other small insects, nor does he take amiss medium-sized 

 beetles, in fact there is one, Disonycha quinquevittata, a regular 

 pest on a sand-binding willow (Salix longifolia), which seems to 

 form a goodly proportion of the tiger's food. The larvae of 

 C. manitoha, while very similar to other species, are quite original 

 in their methods of constructing a burrow. Other species have 

 nearly a straight hole usually at right angles to the surface, but 

 manitoba constructs a cup-like pit into which the butrow enters 

 horizontally from one side and then gradually curls downwards to 

 a perpendicular position, The advantage of this is that it forms 

 a regular death trap to the unsuspecting insect which happens to 

 be crawling near. Possibly this simple method of procuring food 

 is at least in part responsible for the larger size of the species. 



Returning again to the centre of the sand we encounter a 

 longish valley blown a'most down to water and sheltered by sand 

 banks. Here on a hot day, we shall encounter all the tiger beetles 

 already mentioned, as well as ohliquata, 12-guttata and repanda. 

 Among the wet sand here are numerous heaps of sand evidently 

 shoved up by an animal burrowing straight downwards. Select a 

 fresh one and dig carefully to five or six inches and you will 

 discover a roundish beetle rather like a large lady-bird beetle 

 superficially, which in reality, however, belongs to the Carabidae 

 and is Omophron americanum. 



In the higher spots are the larval holes of another tiger beetle 

 called C. Jepida. They are right on the drifting sand and one 

 wonders how the insects manage to keep their holes open or 

 procure sufficient food in such a desert. As a matter of fact there 

 is evidence to indicate that such unfavorable conditions have at 

 least lengthened the larval life to a year beyond the average. 

 Should we be lucky enough to discover a mature larval burrow we 

 might, at this time, trace from it that of the pupal chamber which 

 is the longest I have yet com^ across. Th^ larva whan miture 



