HARDWICKE'S SCIENCE-GOSSIP. 



(>Z 



At the sixth moult the insect becomes a pupa, and 

 at the seventh (being now five years old *) it assumes 

 the form of the perfect insect. The following moults 

 are annual, and like fertilisation and oviposition, 

 take place in the summer months only. He tells us 

 further that the ova require about a year for their 

 development. These statements are partly based upon 

 observation of captive cockroaches, and are the best 

 accessible, but they require confirmation by inde- 

 pendent observers, especially as they altogether differ 

 from Hummel's account of the life-history of Blatta 

 Germanica, and are at variance with the popular belief 

 that new generations of the cockroach are produced 

 with great rapidity. The wings and wing-cases 

 appear first in the pupa-stage, but are then rudi- 

 mentary, and constitute a mere sculpturing of the 

 dorsal plates of the thoracic rings ; the white ocelli 

 internal to the antennary sockets appear first in the 

 pupa. The insect is active in all its stages, and is 

 therefore with other Orthoptera described as under- 

 going "incomplete metamorphosis." After each 

 moult it is for a few hours nearly pure white. Of the 

 duration of life in this species we have no certain 

 information, and there is great difficulty in procuring 

 any. 



We have before us a long list of parasites which 

 infest the cockroach. There is a conferva, several 

 infusoria, nematoid worms (one of which migrates to 

 and fro between the rat and the cockroach), as well 

 as hymenopterous and coleopterous insects. The 

 cockroach has a still longer array of foes, which 

 includes monkeys, hedgehogs, cats, rats, birds, 

 chamseleons, and wasps, but no single friend, unless 

 those are reckoned as friends which are the foes of 

 its foes, 



A few lines must be added upon the popular 

 and scientific names of this insect. Etymologists 

 have found it hard to explain the common English 

 name, which seems to be related to cock and roach, 

 but has really nothing to do with either. The lexico- 

 graphers usually hold their peace about it, or give 

 derivations which are absurd. Mr. James M, Miall 

 informs us that ' ' Cockroach can be traced to the 

 Spanish cucardcha, a diminutive form of cuco or coco 

 (Lat, coccum, a berry), Cucardcha is used also of the 

 woodlouse, which, when rolled up, resembles a berry. 

 The termination -dcha (Ital, -accio -accia) signifies 

 jHcan or contemptible. The word perhaps reached us 

 through the French ; at least coqtieraches has some 

 currency (see for example Tylor's ' Anahuac,' 

 p. 325)." The German word Schabe, often turned 

 into Schtuabe, means perhaps Suabian, as Moufet, 

 quoting Cordus, seems to explain (" Insectorum Thea- 

 trum," p. 138), Franzose is another German word 

 for the insect, applied specially to Blatta Germanica, 

 and both Schabe and Franzose would be thus inter- 

 preted as geographical descriptions, implying some 



* Cornelius says four, but this conflicts with his own account. 



popular theory as to the native country of the cock- 

 roach. Kakerlac, much used in France and French- 

 speaking colonies, is a Dutch word of unknown 

 signification. The name Blatta was applied by the 

 ancients to quite different insects, of which Virgil 

 and Pliny make mention ; Periplaneta is a modern 

 generic term, coined by Burmeister. 



Of the uses to which cockroaches have been put 

 we have little to say. They constitute a popular 

 remedy for dropsy in Russia, and both cockroach-tea 

 and cockroach-pills are known in the medical practice 

 of Philadelphia, 



SCIENCE-GOSSIP. 



A WRITER who signed himself C., recently gave 

 an account in " St. James's Gazette " of an " experi- 

 ment with Hachish " upon himself. His narrative of 

 the visions he saw exceeds what Alexandre Dumas or 

 any other writer ever declared of this Indian drug. 

 He was under its operation for more than four hours, 

 but woke none the worse for the experiment, unless 

 the tendency to eat a great supper at midnight is to 

 be regarded as a misfortune. 



Our readers will remember the interesting inci- 

 dent of small jelly-fishes appearing in the freshwater 

 tanks of the Horticultural Society a few years ago. 

 They excited much attention, and turned out to be 

 new species, but the most singular fact about them 

 was that they should assume freshwater conditions, 

 instead of marine. Dr. Bohn, a Prussian geographer, 

 travelling in Africa, has just sent word he has dis- 

 covered freshwater medusae in Lake Tanganika, 

 They possess a broad, umbrella-shaped disk, and 

 have numerous long and prehensile tentacles. 



Experiments have been going on on one of the 

 shorter American railways, to see whether the wire- 

 fences on either side the line cannot be used for 

 telegraphing purposes, the wires at the level crossings 

 being run under, so as to make them continuous. It 

 is stated that the experiments prove the possibility of 

 the thing being done. 



M, Trepied, of Algiers, has spectroscopically ex- 

 amined the Pons-Brook comet, and found its spec- 

 trum to consist of two bands in the green of different 

 degrees of brilliancy, and a third faint band in the 

 blue. He states that these bands are practically iden- 

 tical with those seen in the spectrum of an alcohol 

 flame. 



We are exceedingly sorry to have to record the 

 death of an old contributor to our Botanical columns, 

 Mr, Thomas Brittain, the well-known Lancashire 

 botanist, died at Urmston, near Manchester, at the 

 end of January. He was President of the Manchester 

 Microscopical Society, A fine, genial old man, be- 

 loved and respected by all, has passed away. 



