ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 445 



appear to be very clean in tlieir ways and persons. Various expei-i- 

 ments seemed to establish tbe fact that these slave-makers always 

 keep a guard ready at once for any attack. 



Chorda Supra-spinalis of the Lepidoptera and the Nervous 

 System of Caterpillars.* — Herr J. T. Cattie commences by describing 

 the ventral vessel and symj)athetic nervous system of Acherontia 

 atropos ; he finds that in that insect there is no paired system connected 

 with the azygos nerves, and that the vagus system consists only of 

 the nervus reciirrens. He finds that from the first to the last ventral 

 ganglion the sympathetic nervous system of the median nerves forms 

 a connected whole, and that it is in direct connection with the tracheae 

 of the wings ; the small lateral sympathetic ganglia of the head 

 innervate the tracheae, but they have no connection with the antennary 

 nerves. He describes nervi laterales transversi as connected with the 

 thoracic ganglia, and two delicate nerve filaments as taking their 

 places in. the abdominal ganglia. He believes that the chorda of 

 Acherontia atropos consists of gelatinous connective tissue, and that 

 it has the function of a lymphoid organ. 



Beaded Villi of Lepidoptera-scales-t— Dr. Eoyston-Pigott claims 

 to have discovered, in carrying out the investigation of the molecular 

 structure of insect scales with a power of 3000, that "the striated 

 surfaces of these scales, though appearing approximately beaded, are 

 really covered with villi, chenille or velvet pile, terminating in a 

 spherule. The recognized object of these striae, regarded as cor- 

 rugations, is to give strength to a most delicate tissue, which are 

 again supported by cross strice. Upon these transverse striae are villi 

 erected upon them by twos and threes, and summits consisting of a 

 refracting spherule." The object upon which these villi were first 

 detected was the scale of Vanessa Atalanta or Red Admiral. 



Histolysis of the Muscles of the Larva during the Postem- 

 bryonic Development of the Diptera-J — M. H. Viallanes has made 

 more than 400 sections of the hardened larvae and pupge of Musca 

 vomitoria. He finds in the larva that the primitive muscular fibre in 

 transverse section presents a sarcolemma containing the central mass, 

 in which may be made out Cohnheim's areas and nuclei. From the first 

 day of pupal life these fibres begin to disajDpear in one of two ways, 

 both of which may be seen in the same animal. 



a. Disappearance of the muscle accompanied by j)roliferation of the 

 nuclei. — The sarcolemma disappears even before the puj)a has taken 

 on its characteristic brown colour ; the contractile substance becomes 

 homogeneous, the lenticular nuclei acquire a spherical shape, and 

 become complete cells, surrounded by a layer of protoplasm and an 

 enveloping membrane. Four or five spherical granules appear in the 

 protoplasm, and by growth become as large as the nucleus ; on the 

 disappearance of the membrane these bodies separate from the 



* Zeitscbr.f. wiss. Zool., xxxv. (1881) pp. 304-21 (1 pi.), 

 t Proc. Koy. Soc, xxxi. (1881) pp. 505-6. 

 X Comptes Reudus, xcii. (1881) pp. 416-18, 



Ser. 2.— Vol. I. 2 « 



