878 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
prothoracic gland of D. vinula ; and, after a discussion of the homologies of 
prothoracic glands, he concludes that there exists a fairly complete series 
which commences with projecting setiparous warts or tubercles surround- 
ing a glandular opening, and leads up to invaginated spiny (setiparous) 
tubes placed laterally to the opening of the median gland. This evidence 
appears to him sufficient to justify the supposition that these lateral 
structures are directly derived from setiparous projections of a Choetopod 
ancestor, and he maintains that the spines now present in the lateral 
tubes of D. vinula and other species are the actual representatives of 
original setae. The glands under discussion, he concludes, are the 
homologues of the coxal glands, and of the acicular gland sacs of 
Chaetopods, while the lateral appendages (spiny projections or tubes) 
represent groups of parapodial setae. 
Sympathetic System of Orthoptera.* — L. Bordas has studied the 
sympathetic nervous system of 25 species belonging to the Phasmidae, 
Blattidae, Mantidae, Acridiidae, Locustidae, and Gryllidae. There is 
great uniformity throughout. The system begins at the anterior end 
of the pharynx in a large dorsal ganglion, the frontal or buccal. This 
is connected by two large cords with the oesophageal connectives just 
below the brain, and it gives off from its posterior surface the unpaired re- 
current or medio- anterior nerve, running to the oesophageal or hypocerebral 
ganglion, which varies greatly in degree of development. There is also 
a lateral ganglionic system in the oesophageal region, with two pairs of 
ganglia with which the unpaired ganglion is connected. The anterior 
pair are connected with the lower surface of the brain, and with the 
posterior pair ; they give off numerous branches to the lateral walls 
of the oesophagus and to the salivary glands. There is indeed an 
oesophageal plexus. The hypocerebral ganglion gives off posteriorly 
a posterior recurrent nerve or pair of nerves, with which the paired 
or unpaired abdominal ganglia are connected. 
Function-Change in Moulting Hairs of Insects. | — Dr. K. Escherich 
describes two cases where the cuticular processes or hairs which are of 
use in loosening the old cuticle take on a new function. (1) In the 
expanded end of the invaginated ductus ejaculatorius, which Verhoeff 
calls the praeputium, there are fine spines, hooks, and the like, which 
help to secure the hold in copulation. These correspond to moulting 
hairs. (2) On the pleural and intersegmental membranes of some 
Meloidse (Meloe variegatus, &c.), where there is considerable strain, due 
to the large number of eggs, there is a variable arrangement of ridges 
running parallel to the folds of the skin, i.e. at right angles to the 
folding force. These ridges are, without doubt, strengthening struc- 
tures, which do not interfere- with the necessary elasticity ; and the 
author compares their effect to that of a string wound round an india- 
rubber tube. They also protect the regions left uncovered by the short 
and delicate elytra. Now it is interesting to find that these ridges 
sometimes consist of small lamellae, and are doubtless, in all cases, 
derived from moulting hairs. 
* Comptes Rendus, cxxv. (1897) pp. 321-3. 1 ^ 
f Biol. Centralbl., xvii. (1897) pp. 542-4 (1 fig.). 
