13 2 Mosquitoes 



alike in all respects save that one is somewhat the deeper 

 in the most dependent part, and contains more or less 

 water, stocked with minnows the year round. In the latter 

 part of September both depressions were filled to about 

 the same level by an unusually hard rain that succeeded 

 a drought of sixty or more days. Exactly four days after 

 this rain the Ashless pool contained the larvae of G.jamai- 

 censis and Janthinosoma posticata in abundance, and a few 

 larvae of O. bimaculatus. Psorophora ciliata and Howard ii 

 were full grown, ornearlyso, as was shown by the pupation 

 of many of them the following day; while a prolonged and 

 most diligent search failed to reveal thepresenceof asingle 

 larva of any species in the pool that sheltered the minnows. 

 From a third pool much smaller and about two hundred 

 yards above, that was conspicuous for the absence of min- 

 nows, were also taken a large number of J. posticata and 

 a few of both species of Psorophora. Again, during the 

 summer just passed repeated examinations were made of 

 the rice fieldsbelow Baton Rouge while they were flooded, 

 with the invariable result of our failure to find mosquito 

 larvae; but minnows were everywhere in evidence and in 

 enormous numbers. Two weeks or more after the water 

 had been withdrawn (and presumably the minnows with 

 it, since they usually swim with the current), leaving 

 many pools and puddles in natural depressions and imper- 

 fectly graded ditches, whose continuity was maintained by 

 frequently recurring showers of rain, we found mosquito 

 larvae in plenty, and during the early morning and late 

 evening mosquitoes in such quantities that we dare not 

 venture a story of our experiences or an estimate of the 

 numbers of insects, lest it should be regarded as extremely 

 ' fishy,' although the large fish were all dead, a fact forcibly 

 impressed upon our olfactories at previous visits by the 



