CLASS V. INSECTA. 301 



Genus 551. OC^TTERYX. Leach. Ocyptkua. Latr. Exorista. 

 Melg. Eriotiirix. Meig. 

 Antenna: with ihoir last joint longer lliun the others : abdomen distinctly 



annulated, rovnidcd. 

 Sp. 1. Oct/pt. lateralis. Leach. 

 Inhabits woods. 



Genus 552. GYMXOSOMA. Melg., Leach. 

 .4/?fc««iS with their last joint longer than the others: abdomen semi- 

 circular, subuniarticulate. 

 Sp. 1. Cum. rotundata. Meig. 



Genus 553. ECIIINOMYIA. Bvm., Latr., Leach. Taciiina. 



Meig., Fabr. 

 Antenncc with their second joint longer than the others : abdomen sub- 



glubose, and very bristly. 

 Sp. 1. Ech. grossa. Latr. 

 Inhabits woods. 



Genus 551.. TACHIXA. Leach. 

 Antemue with their secord joint longer than the others : abdomen 



ovate, rather bristly. 

 Sp. 1. Tach.fera. 

 Inhabits the skirts and patliways in woods. 



Fam. XV. CEstrid.i.. Leach. 

 Mtjscides, I. Lalreille. Astomata. Dumcril. 



The larvge of all the insects of this family reside in the frontal 

 sinuses under the skin, or in the stomachs of graminivorous mam- 

 malia. Their curious oeconomy has been admirably detailed m the 

 third volume of the Transactions of the Linnean Society of London 

 by Mr. Bracy Clark, who has lately republished his Dissertation 

 under the title An Essai/ on the Bots of Horses and other Animals. 

 London, 1815. 



Genus 555. CESTRUS of anthors. 

 Wings with the two exterior cells complete, the other hinder cells ter- 

 minal : thorax with its surface unequal : abdomen with its point de- 

 tiexed; of the female acuminate : fyr.s distant; of the male closer 

 than those of the female. 



* Thorax roughish, tciih elevated points. 



The larvae of the species of this division of the genus inhabit the 

 frontal sinuses. 



Sp. 1. (Esirus Ovis. 



Inhabits the frontal sinuses of the sheep in the larva state ; the per- 

 fect insect is lound on walls and stones in the vicinity of sheep- 

 folds. 



