6 



rant its being recommended as a means of eradicating even the much 

 more disagreeable insect referred to.^ 



The local spread of roaches from house to house is undoubtedly 

 often effected by their introduction with supplies, furniture, goods, 

 etc. That the Croton bug, or German roach, and probably the other 

 species also, may develop a migratory instinct has been witnessed by 

 Doctor Howard and the writer in Washington. (See Insect Life, Vol. 

 VII, p. 349.) 



This very interesting instance of what seems to have been a true 

 migration, in which an army of thousands of roaches by one common 

 impulse abandoned their old quarters and started on a search for a 

 more favorable location, illustrates, as pointed out by Doctor Howard, 

 what is probably of frequent occurrence under the cover of darkness, 

 and accounts for the way in which new houses frequently become sud- 

 denly overrun with these vermin. 



TRANSFORMATION. 



The roach in its different stages from egg to adult shows compara- 

 tively little variation in appearance or habits. The young are very 

 much like the adults, except in point of size and in lacking wings, if 

 the latter be winged in the adult state. In their mode of oviposition 

 they present, however, a very anomalous and peculiar habit. The 

 eggs, instead of being deposited separately, as with most other 

 insects, are brought together within the abdomen of the mother into 

 a hard, horny pod or capsule which often nearly fdls the body of the 

 parent. This capsule contains a considerable number of eggs, the 

 number varying in the different species, arranged in two rows, the 

 position of the eggs being indicated on the exterior of the capsule by 

 transverse lateral impressions. When fully formed and charged with 

 eggs the capsule is often partly extruded from the female abdomen 

 and retained m this position sometimes for weeks, or until the young 



' The following interesting letter from Mr. Herbert H. Smith, the collector and 

 natm-alist, gives a vivid picture oi the roach nuisance in the Tropics: 



Cockroaches are so common in Brazilian country houses that nobody pays any 

 attention to them. They have an unpleasant way of getting into provision boxes, 

 and they deface books, shoes, and sometimes clothing. Where wall paper is used they 

 soon eat it off in unsightly patches, no doubt seeking the paste beneath. But at 

 Corumba, on the upper Paraguay, I came across the cockroach in a new role. In 

 the house where we were staying there were nearly a dozen children, and every one 

 of them had their eyelashes more or less eaten off by cockroaches — a large brown 

 species, one of the commonest kind throughout Brazil. The eyelashes were bitten 

 off irregularly, in some cases quite close to the lid. Like most Brazilians, these chil- 

 dren had very long, black eyelashes, and their appearance thus defaced was odd 

 enough. The trouble was confined to children, I suppose because they are heavy 

 sleepers and do not disturb the insects at work. My wife and I sometimes brushed 

 cockroaches from our faces at night, but thought nothing more of the matter. The 

 roaches also bite off bits of the toe nails. Brazilians very properly encourage the large 

 house spiders, because they tend to rid the house of other insect pests. 

 [Clr. 51] 



