72 Journal New York Entomological Society. [Vol. xiv. 



seeking blood at night are themselves the victims of an anomaly and 

 acting under a morbid impulse, perhaps produced by a parasite. Per- 

 haps there is here some relation with the agent of yellow fever ! 



The third chapter, " biological details," contains a great deal of 

 interest, and it is to be regretted that the details, particularly of larval 

 structure, are not more full. The plates that accompany this chapter 

 are of great interest, particularly the figures from photographs of eggs, 

 larvae and pupae, more or less magnified. The figures from drawings, 

 we are sorry to say, are not equally commendable, and, at least in 

 some cases, appear superficial and inaccurate. Some of these inaccu- 

 racies will be pointed out in connection with the following notes. 

 Sixteen species of Culicidse, three Chironomi< 33 and a Simulium are 

 dealt with, but of some of the species the early stages remain unknown 

 and only notes upon the imago are given. 



Culex fatigans and Stegonixia fascia fa are treated most fully, and 

 each of these species is illustrated by two double-page plates. One of 

 these plates is entirely given up to the eggs of Culex fatigans, and the 

 figures, from photographs, of the eggs singly and in rafts, are very 

 excellent. As the author remarks, these eggs do not appear to differ 

 in any way from those of Culex pipiens. Regarding the small globule 

 at the pointed end of the egg, the writer at first followed the supposi- 

 tion of previous writers that it is air. Closer study of its optical qual- 

 ities and behavior in various liquids used in microscopic technique 

 showed that it is of a gelatinous or mucilaginous substance. The 

 globule is detached by the slightest pressure and in the water swells 

 and then disappears altogether. At the same time the author became 

 convinced that the entire base of the fresh egg- raft is covered by a 

 layer of gelatine, similar to the substance present in so many other 

 insect eggs, and even those of vertebrates. He attributes a hydrostatic 

 function to the globule. Both the globule and the lower layer disap- 

 pear before the breaking up of the egg-boat, which begins soon after 

 the larvae have hatched. The author thinks that this gelatinous sub- 

 stance may perhaps furnish the first food to the young larvae. The 

 cup-shaped appendix on the rounded end of the egg has been figured 

 by several authors, but without comment. The author thinks it is con- 

 nected with the intra-ovarial period, the remnant of the germinative 

 chamber and entirely without physiological significance after the egg 

 is laid. The figure of the sculpture pattern of the interior of the cup 

 shows series of points arranged around a central round depression. 



