78 PRINCIPAL HOUSEHOLD INSECTS. 



from the thorax, and, while not very long, they are powerful and enable 

 the insect to run with great rapidity. 



In certain peculiarities of structure, and also in their habits, these 

 anomalous insects much remind one of roaches, and their quick, gliding 

 movements and flattened bodies greatly heighten this resemblance. 

 More striking than all, however, is the remarkable development of the 

 coxie or basal joints of the legs in the silver fish, which finds its counter- 

 part in roaches, and, taken in connection with the other features of 

 resemblance, seems to point to a very close alliance between the two 

 groups, if, indeed, the silver fish are not merely structurally degraded 

 forms of roaches and to be properly classed with the Blattida?. 



The general distribution of the insect about rooms, in bookcases, 

 and under wall paper renders the application of insecticides difficult 

 and often impracticable. It readily succumbs to pyrethruin, and where- 

 ever this can be applied, as on book shelves, it fuvnishes the best means 

 of control. For starched clothing and similar objects liable to be 

 injured by it there are no means except frequent handling and airing 

 and the destruction by hand of all specimens discovered. Little dam- 

 age is liable to occur in houses except in comparatively moist situ- 

 ations or where stored objects remain undisturbed for a year or more. 



Another of the common silver fishes of this country, referred to in 

 the opening paragraph, has developed a novel habit of frequenting 

 ovens and fireplaces, and seemingly revels in an amount of heat which 

 would be fatal to most other insects. It disports itself in numbers 

 about the openings of ranges and over the hot bricks and metal, mani- 

 festing a most surprising immunity from the effects of high tempera- 

 ture. This heat-loving or bakehouse species (fig. 33) was described in 

 1873 as Lepisma domestica by Packard, who reported it to be common 

 about fireplaces at Salem, Mass. This species is also very abundant in 

 Washington. What is evidently this same insect has become very com- 

 mon, particularly in the last year or two, in England and on the Conti- 

 nent, where it manifests the same liking for hot places exhibited by it 

 in this country. The habit of this species of congregating in bake- 

 houses and dwellings, about fireplaces and ovens, has given rise to the 

 common appellation for it in England of " fire-brat." Similar descriptive 

 names are applied to them also on the Continent. This species closely 

 resembles the common silver fish in size and general appearance, but 

 may be readily distinguished from it by the presence on the upper 

 surface of dusky markings. It also possesses well-marked structural 

 differences, which have led to its late reference to a distinct genus — 

 Thermobia. An Italian entomologist, Eovelli, has described this insect 

 under the descriptive name furnorum, from its inhabiting ovens, and 

 the name of the genus to which it is now assigned by English entomolo- 

 gists is also descriptive of its heat-loving character. A Dutch ento- 

 mologist, Oudemans, reports that he has found it in abundance in all 

 bakehouses that he has examined in Amsterdam, where it is well known 

 to bakers and has received a number of familiar names. 



