37 



extent in size and colour ; the length of forceps is very unstable. In 

 Spongophora parallela, Westw., this organ varies from 4 mm. to 

 1 8 mm. in length, and the common Forficula auricu/aria, L., it may 

 be a few millimetres or as long as the whole body. 



It is not an uncommon thing to find examples of gynandromor- 

 phism. I possess two such Chelisoches morio (Fabr.), and de Bormans 

 records the same phenomenon in Forcipula pugnax (Kirb.). So small 

 a percentage — about 400 — of the existing number of species is known 

 to science that in almost every collection of earwigs received from 

 abroad there are two or three novelties — a fact which is as encourag- 

 ing for the collector as it is discouraging for the systematist. 



Of Blattodea nearly a thousand species are known, but their 

 classification is a matter of considerable difficulty. Again and again 

 Brunner and de Saussure have published memoirs on them, but 

 yet still the subject is not in a satisfactory condition. In his " Me- 

 langes Orthopterologiques," " Biologia Centrali- Americana," and 

 several papers on Panaesthediae, Epilampridae, Perisphaeridae, and 

 Heterogamidae, de Saussure has advanced our knowledge, and the 

 weighty contributions of Brunner von Wattenwyl are to be found in 

 his " Nouveau Systeme des'Blattaires " and " Revision du Systeme des 

 Orthopteres." 



Although cockroaches are now reckoned among our most lowly and 

 plebeian insects, if length of pedigree goes for aught, they have 

 a claim to be reckoned among the aristocracy of nature, for they can 

 trace back their descent to the carboniferous period ; in fact, the pre- 

 sent day is the period of their decline. The majority of existing 

 insects are upstarts and parvenus, now in their golden age. Before 

 these were evolved cockroaches swarmed in the carboniferous forests 

 in numbers that would have put to shame any modern self-respecting 

 London kitchen ! 



It is a very common mistake to regard cockroaches as ugly dull- 

 coloured creatures. This is the fault of that much-maligned species, 

 Blatta orient 'a/is, L., which is, as has been so often pointed out, 

 neither black nor a beetle, neither a cock nor a roach. That this 

 claret-coloured, albeit sombre, fellow should be taken as representative 

 of his whole section is a misfortune for his relatives, many of whom, 

 so far from being modest in colour, like our friend in question, are 

 bright and gaudy in stripes and spots of various tints. 



A glance at one of de Saussure's coloured plates will dispel this 

 illusion. In England we have the rich red Periplaneta americana (L.), 

 and its near relative, P. australasice (Fabr.), which adds handsome 

 yellow markings to the red. These are all, no doubt, familiar to you. 

 But the species of Phoraspis, Corvdia, Hypnorna, and others are of 

 bright colours, variegated with spots and stripes. The huge Blabera 

 are pale straw-coloured ; and oddest of all are Panchlora, clad, as 

 their name implies, entirely in pale green, which fades to white after 

 death. 



Cockroaches are attacked by parasites of the groups Protozoa, 



