CLASS V. INSECTA. 301 
Genus 551. OCYPTERYX. Leach. Ocvptera. Lutr. Exorista. 
Meig. Eiiiothuix. Meig. 
-Antenna with their last joint longer than the others : abdomen distinctly 
annulated, rounded. 
®p. 1. Ocypt. lateralis. Leach. 
Inhabits woods. 
Genus 552. GYMNOSOMA. Meig., Leach. 
■Antenna with their last joint longer than the others: abdomen semi- 
circular, subuniarticulate. 
Sp. 1. Gym. rotundata. Meig. 
Genus 553. ECHINOMYIA. Bum., Lutr., Leach. Taciiina. 
Meig., Fair. 
Antenna with their second joint longer than tire others : abdomen sub- 
globose, and very bristly. 
Sp. 1. Ech. grossa. Latr. 
Inhabits woods. 
Genus 554. TACIIINA. Leach. 
Antenna with their second joint longer than the others : abdomen 
ovate, rather bristly. 
Sp. 1. Tuck. fern. 
Inhabits the shirts and pathways in woods. 
Fain. XV. (Estkida.. Leach. 
Musci des, I. Latrcil/e. Astomata. Burner il. 
The larva: 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 ceconomy has been admirably detailed in the 
third volume of the Transactions of the Linneun Society of London 
by Mr. 13 racy Clark, who has lately republished his Dissertation 
Under the title An Essay on the Bots of Horses ami other Animals. 
London , 1815. 
Genus 555. CESTRUS of authors. 
iTings with the two exterior cells complete, the other hinder cells ter- 
minal : thorax with its surface unequal : abdomen with its point de- 
flexed; of the female acuminate : eyes distant; of the male closer 
than those of the female. 
* Thurac roughish, with elevated points. 
The larva 1 of the species of this division of the genus inhabit the 
frontal sinuses. 
®P- 1. (Estrus Ovis. 
Inhabits the frontal sinuses of the sheep in the larva state ; the per- 
fect insect is found on walls and stones in the vicinity of sheep- 
folds. 
