223 



weakly about. The song of Clcadi/ ii/(uylii(/f(/. resembling that 

 of the periodical cicada, was heard; and in the twilight came 

 the penetrating shrilling of Couorcpluihoi rahnsfiis, and the rat- 

 tling note of the male of Hcnoclicihis p(irado.rMS, as moths of 

 the latter species danced in groups here and there. 



The abundant wild Howers were visited l\v large numbers 

 of bees, wasps, and other aculeate Hiimcinipfeni, many of which 

 were species rarely or never seen on the prairie,— Z>/>//.s plit- 

 mipes, for example, — probably associated with the unusual floi'a. 

 Families which nest in sand were well repre.sented, such as the 

 Larriiht', which capture young OrtlKqitcnt to provision their 

 nests, the Bi-iiibccldd', which use flies for this purpose, and the 

 bee family Co/Iffldtr. In fact, this kind of region seems partic- 

 ularly favorable to the development of these insects in great 

 numbers and variety because of the undisturbed ground and 

 vegetation in addition to the character of the soil. Hoppner 

 ('01 ) shows that similar conditions prevail in a tract of dune 

 sands along the Weser valley in Germany, flnding there six 

 characteristic local species of bees, and three others more 

 abundant there than elsewhere, the total list including two 

 thirds of all the bees found in northwest ({ermany. To de- 

 velop this subject for our district would require vastly more 

 time than was available. 



The insects associated with some of the more common 

 plants of the sand region may next be grouped under their re- 

 spective plants. 



Mesodenia <driid/clf(diii. — This may well head the list of 

 host plants, with its interesting insect guests. On the flowers 

 of scattered clumps of these plants were two far western spe- 

 cies, a large tenebrionid ( Epif rat/us ticufiis ] and a long-legged re- 

 duviid {ZeJus surliis). also Li/f/a^ns bi<-ntri>i, and, upon the stems, 

 Laiif/iiria himlor. the larvie of which burrow in the stems. 



Opiinfia Iniiinf/isa. — This cactus was usually abundant, and 

 sometimes supported flourishing coloniesof PeidnfiuHd juniprri- 

 nu. It was also responsible for the presence of the bright-yel- 

 low-striped chunky little syrphid tly, Voliicella fasciata, seen 



