126 



aquatic JLiU 



of the eggs will have been devoured by 

 the adults. 



The youngsters, after the yolk-sac has 

 been absorbed, must be furnished with 

 abundant Infusoria water — plenty of it. 

 After a week or so, as they grow larger, 

 they can be given the finest powdered 

 insect food, followed gradually with 

 tiny screened Daphne and Cyclops. If 

 the temperature is maintained high 

 enough the little fellows can be almost 

 seen to jump in size. 



The Giant Danio, Danio malabaricus, 

 the largest of the genus known to the 

 aquarist, is undoubtedly the handsomest 

 of all our tropical aquarium fishes. 



A Chapter in the 

 Life -History of a Beetle 



ERNEST LEITHOLF 



Last summer, while collecting in the 

 vicinity of Pittsburgh, I secured two 

 small aquatic beetles, a male and a fe- 

 male, of the family Hydro philidae. I 

 was unable to determine the species. 

 The specimens were elliptical in shape, 

 the back olivaceous brown, and measur- 

 ed about three-eighths of an inch long. 

 While under water, and in the sunshine 

 their abdomens, covered with a thin film 

 of adhering air, sparkled and glistened 

 like silver. 



I placed the pair in an aquarium 

 containing a yellow-bellied terrapin, a 

 Cumberland Painted Turtle and a com- 

 mon newt, Diemyctylus viridescens, 

 knowing that in this mixed company the 

 new arrivals could at least work no 

 harm. At first the beetles were kept busy 

 dodging the charges of the older in- 

 mates, but these soon ceased. 



Shortly after I discovered a white 

 needle-like spire which projected about 

 an inch and a quarter above the water 

 and had its origin in a pouch resting in 

 a cluster of Salvinia roots. Twenty-four 

 hours later another spire appeared close 



by. I was now quite interested and, for- 

 tunately, did not have long to wait ere 

 their origin was explained. The build- 

 ers were the beetles. I discovered them 

 at work on a third spire in the position 

 shown by my sketch. The male, head 

 downward, was partly submerged, while 

 immediately above him the female, also 

 head down, was discharging a continu- 

 ous and scarcely discernable stream. The 

 fluid, which seemed to be gelatinous in 

 consistency, unerringly found its mark 



at the summit of the structure and con- 

 gealed. In an hour the spire was as tall 

 as the others, then both beetles slipped 

 back into the water. 



Unfortunately my observations come 

 to a close at this point. The nest was 

 destroyed soon after, and one of the 

 beetles disappeared. In examining the 

 wreck I discovered that the spires were 

 hollow; hence probably served as shafts 

 to supply air to the eggs in the cocoon 

 below the water surface from which 

 they rose. 



(The color of the beetle as well as the 

 type of egg-sac would seem to place it 

 in the genus Helophorus. The spire is 

 for the purpose of admitting air to the 

 egg mass. The shape of the tube differs 

 in the different genera. This year Mr. 

 Leitholf hopes to again collect this 

 beetle and complete his study of its life- 

 historv. — Editor) . 



