NO. 13 STAPHYLINIDAE BLACKWELDER 2$ 



side. The anterior half of the scutellum is very densely invested with 

 short fine setae, and the posterior half has two large lateral, finely 

 strigulose areas bearing numerous circular and occasionally anastomos- 

 ing pores of unknown function. 



The scutum of the metathorax is divided into two parts by the ap- 

 proximation of the prescutum and the scutellum. Medially these are 

 separated from the scutellum by the suture of the V-ridge, but posteri- 

 orly they are continuous with the lateral extensions of the scutellum 

 to the wing bases. From the prescutum and the axillary and subalar 

 sclerites it is separated by the prescutoscutal suture (figs. 3 A, 4 F, 

 pss). At the sides the combined scutum and scutellum form the 

 posterior notal wing process (pnp), and just anterior to this process 

 are two small invaginations and a process that articulates with the 

 base of the first axillary sclerite (ax. i). The entire surface of the 

 scutum is densely, finely muricate, the posterior median part being 

 likewise strigulose with the minute but rigid points born on the sum- 

 mits of the strigulae. Two small groups of fine setae are present on 

 each area of the scutum. One is on the median lobe (mis) that over- 

 laps the suture of the V-ridge; the other is on the lateral margin just 

 mesad of the articulation of the first axillary sclerite (axp). 



The prescutum is normally almost entirely covered by the mesono- 

 tum, but is readily recognizable in dissections as an irregular band 

 along the anterior border of the scutal areas (fig. 4F). It is rather 

 irregularly and less heavily sclerotized and is broken up into a number 

 of areas or sclerites. The transverse median part bears on its ectal 

 surface a broad lobe (pscl) reflected so as to overlie somewhat the 

 central membranous area between the prescutum and the scutellum. 

 This lobe is exceedingly smooth and flat, without sculpture or vesti- 

 ture of any kind. Near the anterior angles of the scutum, the pre- 

 scutum is broken up into two small sclerites on each side. The inner 

 one is very small and triangular and overlaps the median portion 

 ectad. The outer one is also subtriangular, but it is larger and forms 

 the very blunt anterior notal wing process (anp) which lies under 

 the distal end of the first axillary sclerite (ax. i). These two sclerites, 

 as well as most of the median part, are very minutely muricate, and 

 the membranous central area has a group of minute setae which is 

 continuous with that of the scutellum as described above. 



The postnotum (figs. 3 A, 4 F, pn) is the short transverse sclerite 

 extending across the dorsum from one pleuron to the other and sepa- 

 rated from the scutum and the scutellum by the postnotal suture 

 (pns). It is connected by a very short membrane to the first ab- 

 dominal tergite, and at the sides is reflected around the first abdominal 



