1916] Thoracic and Cervical Sclerites of Insects 57 



In studying the thorax in a series of insects such as Mantispa, 

 Chrysopa, Tipula, Leptis and Tabanus, it will be observed that 

 there is a gradual shifting forward of the sclerites, being most 

 pronounced in the mesothorax (Figs. 13, 1, 2 and 11). This 

 causes the pleural suture of the mesothorax to become more or 

 less crooked as shown in Figs. 1, 2 and 11, pls2. 



Starting at the upper end of the mesothoracic wing fulcrum 

 of Tabanus (Fig. 11, plwp) the pleural suture (plso) runs down- 

 ward and slightly forward in a more or less curved line until 

 it meets the sternopleurite (lower region of the episternum). 

 (Fig. 11, stp). Here it turns almost at right angles and runs 

 posteriorly to the meropleurite (lower portion of epimeron), 

 (Fig. 11, mp) and thence downward and slightly backward to 

 the coxa. This condition is very confusing and hard to see, 

 unless the specimen is first boiled in caustic potash, in which 

 case the pleural suture is readily observable. 



In Diptera the meron is often fused with the lower region 

 of the epimeron, forming the meropleurite (Fig. 11, mp), but 

 as the former sclerite is usually closely connected with the coxa 

 it will be treated under the heading Coxa. 



Audouin, '24, applied the term epimeron to the sclerite 

 immediately posterior to the episternum. This term has been 

 generally accepted and used by nearly all subsequent ento- 

 mologists. The epimeron was termed by Burmeister, '32, the 

 "pleura;" by Verhoeff, '03, the "anopleure;" by Amans, '85, 

 the "postpleuron," and by Heymons, '99, the "pleurite. " 

 Hammond, Brauer and Lowne who have worked on the Dip- 

 teron thorax, where the epimeron is often subdivided into 

 two sclerites, have applied the term epimeron to various 

 thoracic sclerites and the terminology has been greatly confused. 

 Osten-Sacken's terminology for the thorax of Diptera is very 

 good and should be retained. Crampton, '14, in a review of 

 the Dipteron thorax has retained this terminology slightly 

 modified as previously stated. This terminology should also 

 be applied to all insects in which the epimeron and episternum 

 are subdivided as in Mantispa, Chrysopa, etc., since it has been 

 established by wide-spread acceptance among those working 

 on Diptera and should be made a uniform terminology for all 

 insects with a thorax of this nature, as far as possible. 



The term parapleuron has given rise to much confusion 

 among morphologists. It was first applied to the entire pleural 



