218 



on rising is : " How did the mosquitoes treat you last night 1 " 

 Continuing, this great traveller says : " Kot the dangers of navi- 

 " gation in small canoes, not the wild Indians, snakes, crocodiles 

 " and jaguars that are the terror of travellers on the Orinoco, it 

 " is simjjly the mosquito." 



In a recent number of the Journal Mr. Petersen gave us a 

 translation of an article on the part mosquitoes play in spreading 

 the human thread-worm and other entozoic diseases, but although 

 they undoubtedly do some harm they also have theii- good qualities 

 and some benefit is derived from them. In Brehm's Tier/eben 

 Professor Taschenberg tells\is of a cure a Vera Cruz doctor, named 

 Delacoux, effected on a lady suffering from inflammation of the 

 brain. This lady was in a state of somnolence for twelve hours 

 and showed sjmiptoms of approaching death. The doctor put up 

 the mosquito net and opened the windoAvs, allowing the mosquitoes 

 to bite the patient for two hours. The somnolence disappeared 

 and next morning the moribund was not only among the living 

 but seemed to be much better. Mosquitoes also do some good in 

 their larval stage for in Packard's " G uide to the Study of Insects " 

 I find the following : " The larvte remain most of the time at the 

 " bottom [of water] feeding upon decaying matter, thus acting as 

 " scavengers and doing great benefit in clearing swamps of 

 " miasma." Another author says some countries would be 

 uninhabitable owing to fevers, were it not for the mosquito larva?, 

 which clear away the miasma. 



LIFE IIISTOHY. 



The eai'ly life of a mosquito is spent in water. The larvse 

 are found in all stagnant j^ools no matter of what size. It is 

 interesting to watch tb.e doings of these delicate worm-like 

 creatures, as they hang to the surface of the water by their 

 res})iratory tubes which are situated at an angle to the last segment 

 of their bodies, with their heads hanging down ; on these the haired 

 mandibles are in perpetual movement causing a small current, 

 which brings particles of decaying matter within reach of their 

 mouths, by which the digestive canal is soon colored black. Many 

 of these larvse are seen in this position when everything is quiet ; 

 but, disturb the water they are in, and, down they go to the 

 bottom wriggling like so many little snakes ; but they cannot 

 remain without air very long and one by one they take up their 

 former position. But often, without been disturbed, they wriggle 

 down to the bottom of the water and move about, the mandibles 

 hard at work all the time. Such is the life of a mosquito larvae. 

 Skins are changed three times, at intervals of about a week. 

 At the fourth moi;lt the worm-like larvre is transformed into a 

 being with a club shaped body with two respiratory tubes 



