INDIRECT INJURIES CAUSED BY INSECTS. 233 



and injuries of the atmosphere, are of consequence to 

 us: yet these, solid and substantial as they appear, are 

 not secure from the attack of insects ; and even our 

 furniture often suffers from them. A great part of our 

 comfort within doors depends upon our apartments 

 being- kept clean and neat. — Spiders by their webs, 

 which they suspend in every angle, and flies by their 

 excrements, which they scatter indiscriminately upon 

 every thing, interfere with this comfort, and add li uch 

 to the business of our servants. Even ants will some- 

 times plant their colonies in our kitchens, (I have known 

 the horse-ant, Formica riifa, L., do this,) and are not 

 easily expelled. Those of Sierra Leone, as I was once 

 informed by the learned Professor Afzelius, make their 

 w ay by millions through the houses. They resolutely 

 pursue a straight course ; and neither buildings nor ri- 

 vers, even though myriads perish in the attempt, can 

 divert them from it. Numerous are the tribes of insects 

 that seek tlieir food in our timber, whether laid up in 

 store for our future use, employed in our houses, build- 

 ings, gates or fences, or made up into furniture. The 

 several species of Mr. Marsha m's genus Ips (v.hich iii- 

 eludes the coleopterous genera Apate, Bostricliifs, II tj- 

 lesshrus, Ili/lurgus^ Tomicus, Plati/pus, Scoli/tus, and 

 P/iloioiribus o^ modem systematists) all prey upon tim- 

 ber, feeding between the bark and the wood, and manv 

 of them excavating curious pinnated labyrinths. Al- 

 most every kind of tree has a species of this genus ap- 

 propriated to it, and some have more than one''. The 

 Stag-beetle tribe, or Lucanidcc, and several of the wec- 



^ KIrby in Linn. Trans, v. 250. 



