30 INSECTS 



fast to some object. Thus it takes con- ture stages. The Mosquito is a good il- 



stant effort in order to remain below the lustration of this type. In some of its 



surface. For this reason it is quite nat- habits the Mosquito is well known, but 



ural that they should very often be found this is primarily due to the biting habit 



floating at the surface where no effort is of the female. The researches of recent 



needed to maintain their position and years clearly show that the annoyance 



where an abundant supply of air is acces- from the bite itself, is, in the case of some 



sible. kinds of Mosquitoes, only a small part of 



Another method of securing fresh air, the mischief that they can do. The life 

 but differing, from that of any of the in- history of the Mosquito has been sum- 

 sects previously mentioned, is by means marized somewhat as follows by Dr. L. 

 of elongated breathing tubes, thus allow- O. Howard : The eggs are laid at night, 

 ing the insect to remain submerged and in a boat-shaped mass containing from 

 yet secure a fresh supply of air from the two hundred to four hundred eggs. These 

 surface. This method is used by some may hatch in 16 hours, the larval stage 

 predaceous water bugs, as shown in the lasting about a week, and the pupal stage 

 plate, Ranatra fusca. As with all of our about 24 hours. Thus the entire cycle may 

 Predaceous water bugs, which have the be completed in 10 days, under favorable 

 elongated respiratory tube at the end of circumstances, but may be greatly delayed 

 the body, the Water-scorpion has its fore by a low temperature. The rapidity with 

 legs adapted for capturing and holding its which the complete cycle may be passed 

 prey, which consists generally of small through makes it possible for a very large 

 fish and insects. The apical part of the number of broods to occur during a single 

 fore leg folds back on the basal part season. 



which is grooved on its inner face, as a The Wigglers or Wiggle-tails, often so 



knife blade folds into its handle. As the numerous in rain-barrels, are the larvae of 



slender legs of this bug would indicate, mosquitoes. Every one has noticed that 



it is not an active swimmer, but crawls these larvae when not disturbed rest at 



about slowly. the surface, but when frightened drop 



Doubtless the best known, to most peo- slowly downward in the water, since they 



pie, of this type of breather, are the Giant are heavier than this medium, yet they 



water bugs, which accumulate in such rest at the surface, by means of a rosette 



large numbers under and in the globes of of thin plates at the tail end of the body, 



electric lights. The paired nature of the These act as the hairs on the legs of the 



breathing tube is well shown in the plate. Water-strider, and make use of the ten- 



These bugs are powerful swimmers, as is sion of the surface film which holds the 



shown by their flattened hind legs. Even larva up, as the surface tension held up 



young fish are not overlooked by these the Water-strider. On the next to the last 



voracious bugs. A South American kind segment of the Wiggler there is a large 



is much larger than our species, reaching breathing tube which reaches to the sur- 



from four to four and one-half inches in face when the larva is floating. The food 



length, or about twice the size of our of the larva is said to be decaying vege- 



species. The shortness of the air tube table matter. The short pupal period is 



suggests that this organ is not used in also passed floating, but it now has two 



just the same manner as in the Water- breathing tubes near the points of attach- 



scorpions, and the areas of fine hairs on ment of the wings. When ready to trans- 



the under side of the body suggest that form it crawls out onto the pupal skin and 



these insects may be somewhat of a com- dries its wings preparatory to flight, 



promise between those insects which Our common mosquitoes belong to 



carry air below with them and those three genera, Culex, Anopheles and Cor- 



which remain submerged, except for the ethra. The annoyance caused by the irri- 



tube which communicates with the air. tation resulting from the bite is not un- 



Most of the insects previously men- derstood, as no poison gland has been 

 tioned are ones which throughout life live found. The females only of our mosqui- 

 in water, but a very large number are toes are known to suck blood. From re- 

 aquatic only during their larval or imma- searches made during the past few years 



