352 Miscellaneous. 
pensate for the gee due to — evaporation or cutaneous trans- 
piration. The same fact occurs in chrysalids. The cocoon with 
which the pup of 1 dire indes of Lepidoptera and Hymenoptera 
ac 
moment when they are taken out of the cocoon; then, in the air, 
they lose their weight by evaporation, and the surface of their body 
often descends below the temperature of the surrounding air. In 
mperat 
refrigerations due to evaporation are not produced when the tem- 
perature very nearly approaches 32? F., a result perfectly conform- 
able with the results of physical researches 
Sex exerts a marked influence on the evolution of superficial 
heat in certain groups of insects. "ee in the Bombycide the males 
to occur among the Phryganide ao Pieride. But we must be 
careful in generalizing these results. 
The experiments of M. Girard upon the differences of temperature 
2 
longs to all, which agrees well with the analogous dissemination 
is i ase in insects 
very considerable. In the Humble Bees, and especially in the 
Sphingidæ, whose flight is so powerful, the excess of the thoracic over 
the abdominal temperature amounts commonly to from 7° to 11° F., 
or even sometimes to from 14° to 18°F. We may say that in insects 
endowed with aérial locomotion the heat is concentrated in the 
thorax into a focus of intensity proportional to the effective power 
of flight. These results are in conformity with anatomical data. 
equalization of temperature does not take mde so Lee as in the 
vertebrata. we consider a wasp (a Polistes or a Sphex), the abdo- 
men of which is united to the thorax only by a slender peduncle, how 
slowly must the currents of the blood be transmitted between these 
two regions through so narrow a strait! e may see how the heat 
developed in the thorax during the movement of flight must pass with 
difficulty into the abdomen, even if it ever reaches this part. 
Another fact, intimately connected with that just referred to, is a8 
follows. ` M. Girard has ascertained that, in the Humble Bees and 
uzzing. ie temperature falls as soon as the insect eeases to buzz, 
but rises again as soon as the buzzing is resumed ; and this takes 
P lace many times successively.— Annales des Sciences Naturelles; tome 
xi. (1869) p. 134; Bibl. Univ. January 15, 1870, Bull. Sci. p. 83. 
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