NATURAL HISTORY WORK IN CARTAGO 8 1 



to take blood directly from the water or whether they took 

 it from the muzzles of cattle when these chanced to drink 

 at this stream or some of its affluents higher up, but when 

 the stomach of a well-preserved specimen was examined 

 its contents were found to be sand-fly larvae only. These 

 leeches were identified by Professor J. P. Moore as probably 

 Erpohdella triannulata, a species described from Lake Ama- 

 titlan, Guatemala, although larger, some being 3 inches 

 long. There it is said to "abound, seeking concealment by 

 day beneath stones and similar objects in the shallow waters 

 and at night becoming active in the pursuit of small worms, 

 insect larvae and even the smaller members of its own 

 species, which constitute its chief food. Having no toothed 

 jaws it is not an habitual blood sucker, though it doubtless, 

 like related species, attacks abraded surfaces of higher ani- 

 mals when opportunity offers." 



The adult sand-flies were naturally quite abundant and 

 at times troublesome. The bite produces a characteristic 

 mark on the skin. At first there is a red dot surrounded by a 

 paler red circular area which may be one-eighth inch in diam- 

 eter. The next day the surrounding area becomes bluish 

 while the central dot remains red, becoming darker and 

 darker with succeeding days until it is at last almost black and 

 although small (one-fiftieth inch) Is quite conspicuous and 

 raised more or less on the top of a little lump. Meanwhile 

 the surrounding area has resumed its usual color, and these 

 stages may occupy a week or more. The pain and Irritation 

 produced vary much In different Individuals. 



Although dragonflles were our chief objects, we also col- 

 lected Microdiptera regularly at each locality we visited. 

 This was the easiest possible collecting, for all that was nec- 

 essary was to sweep a special form of net (devised by Mr. 

 E. T. Cresson, Jr., for this purpose) over the grass and low 

 herbage, emptying the contents into a cyanide jar. Later, 



