ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 195 



Cricket's Chirps and Temperature.* — Mr. R. T. E les corroborates 

 what Prof. A. E. Dolbear previously noted in regard to the relation of 

 the cricket's chirping to the temperature. fjHe observed the tree-cricket, 

 (Ecanthus niveus, and found on the whole that Dolbear 's formula fits. 

 Let T = temperature in degrees Fahrenheit ; n = number of chirps per 



minute; then T = 50 -f ^-^- • This would give 100 chirps per 



minute for 65°, and more when it is warmer. Keats was right in speak- 

 ing of <; the cricket's song, in warmth increasing ever." A comparison 

 with the rhythm of the pulse as affected by temperature in fever is 

 suggested. 



Sexual Dimorphism in Beetles.f — Mr. G. T. Arrow, in publishing a 

 systematic paper on the genus Parastasia, notices that sexual dimorphism 

 is practically universal in the genus, and secondary sexual modifications 

 occur to about an equal degree in both sexes. The author is unable to 

 suggest any explanation of the meaning of this phenomenon, but believes 

 that it is commoner in insects than has been supposed. 



New Termitophilous and Myrmecophilous Beetles. J — Herr E. 

 Wasruann describes a number of new forms from India. Of especial 

 interest are two Aphodia (Chsetnpisles sulciger and Corythodorus gibbiger) 

 which have degenerate mouth-parts. Only the first maxillae are de- 

 veloped, and the suggestion is plausible that these guests get their food 

 from the mouths of the termites. 



Pygidial Glands of Pheropsophus bohemani Chaud.§ — Herr Fr. 

 Dierckx has had an opportunity of dissecting this beetle, and finds that 

 it has more elaborate defensive organs than any Bombardier beetle yet 

 described. Each gland consists of twelve lobes, each with its own duct, 

 and each lobe consisting of ten lobules. The twelve ducts open into a 

 reservoir, which in its turn opens into a chitinous capsule communicating 

 by a short broad canal with the exterior. The surface of the capsule is 

 covered by unicellular glands, which appear to furnish the particles of 

 solid matter (mitraille) ejected at the explosion, together with the volatile 

 liquid. The author therefore abandons his original suggestion that 

 these solid particles are produced by the pulverisation of fecal matter. 



Development of Wing-covers of Beetles.|| — Herr E. Kriiger finds 

 that the wing-covers of beetles arise from a primordium identical with 

 that which gives origin to the posterior wings. The growth of the two 

 structures is for a time parallel, and then the wing-covers diverge. The 

 wing-lamellse are further apart than in the posterior wings ; the chitini- 

 sation is much more abundant ; there is no venation ; a secondary internal 

 cavity, crossed by chitinous bridges, developes in communication with 

 the cavity of the body. In short, the anterior wings in beetles are not 

 to be regarded as wings inhibited at an early stage in their development, 

 but as divergent structures specialised in relation to a new function. 

 The author follows the development from the imaginal fold stage on- 



* Amer. Nat., xxxiii. (1899) pp. 93.5-8. 

 t Trans. Ent. Soc. Loud., 1S99, pp. 479-99 (1 pi.). 



% Deutsche Entomol. Zeitschr., 1899, pp. 145-61) (2 pis.). See Zool. Central bl., 

 vii. (1900) p 38. § Zool. Anzeie., xxiii. (1900) pp. 15-8 (3 figs.). 



1] Inaug. Diss. Gottingeu, 1898. See Biol. Geutralbl., xix. (1S99) pp. 779-83. 



