468 PROCEEDINGS OF THE NATIONAL MUSEUM. vol. xxxiii. 



here shown may supply many of the missing details, particularly with 

 reference to the structure of the abdomen, the formation of the case 

 or bag in which the eggs are carried, and the details of the antennae, 

 mouth tube, mouth parts, and maxillipeds. 



CECROPS LATREILLII Leach. 



Plates XXXVIII and XXXIX. 



Cecrops .latreillii Leach, 1816, p. 405, pi. xx, figs. 1 to 5.— Hceven, 1857, p. 67, 

 pis. Ill, IV. — Thomson, 1889, p. 362, pi. xxvi, figs. 3 a to/. 



Female. — Carapace oval, as wide as long, witli a prominent frontal 

 margin and a deep triangular posterior sinus. Frontal plates almost 

 entirely fused with the carapace, separated by a wide and deep median 

 sinus. On the lateral margins just behind the frontal plates is a well- 

 defined notch on either side, in the base of which the first antennae 

 are attached. Another notch a little farther back on the lateral 

 margins is caused by the transverse groove which separates the cepha- 

 lic from the thoracic portion of -the lateral areas. This groove is 

 situated far forward, and in consequence the cephalic portion in front 

 of it is small and triangular, while the thoracic portion behind it is 

 nearly four times as large and trapezoidal in form. The second and 

 third thorax segments are fused together and furnished with a single 

 pair of lobes and a single pair of dorsal plates. The broad lateral lobes 

 apparently belong to the second segment, and reach well out beneath 

 the posterior lobes of the carapace. 



The small dorsal plates belong to the third segment and overlap the 

 following segment a little; the fourth segment has a pair of medium- 

 sized plates which reach about to the center of those on the genital seg- 

 ment; each of them is triangular in shape with well-rounded corners. 

 The genital segment with its dorsal plates is enlarged to nearly twice 

 the length of the carapace and is elliptical in form, about one-fourth 

 longer than wide, with the sides very evenly curved. It is covered 

 by a pair of dorsal plates, whose edges are softened and project far 

 beyond the lateral and posterior margins of the segment. These soft 

 edges are rolled over ventrally mto large scrolls which completely 

 cover the sides and posterior end of the segment and lap quite a dis- 

 tance onto the ventral surface, completely concealing the abdomen, 

 anal laminae, and egg-strings in dorsal view. The posterior sinus 

 between these plates is sharply triangular and about one-fourth the 

 entire length of the plates. 



Abdomen semielliptical and fully as large as or often larger than 

 that portion of the genital segment which precedes it. Its ventral 

 surface is produced into a large lobe or lamina on either side, which 

 extends outward laterally beneath the turned-over edge of the dorsal 

 plates of the genital segment (Plate XXXIX, fig. 253). 



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