6 



The c(wkroach is, however, far too much of a nuisance itself to 

 warrant 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 affected by their being introduced 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 Dr. 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 com- 

 mon impulse abandoned their old quarters and started on a search 

 for a more favorable location, illustrates, as pointed out by Dr. 

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

 darkness, and accounts for the way in which new houses frequently 

 become suddenly overrun with these vermin. 



TRANSFORMATION. 



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

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

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

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

 the}^ 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 fills 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 



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

 and naturalist, gives a vivid picture of 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 i)aper 

 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 

 tlie lid. Like most Brazilians, these children 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. 



