ORTHOMORPHA. 159 
narrow ledge. Antenne and legs moderately long, or long and slender. Caudal process narrowed 
posteriorly with truncate apex or subcylindrical. Phallopods moderately large, the distal segments 
showing division into two or even three elements, sometimes simple, sometimes branched towards the 
end, the seminal stile in the latter case lying at all events usually on the upper (adoral) side of the 
appendage and the guard or sheath on the lower or aboral side. 
Distribution. Tropical and temperate zones of both Eastern and Western Hemispheres ; 
but not as yet recorded as indigenous in Central America. 
ORTHOMORPHA. 
Paradesmus, Section III., Saussure, Linn. Ent. xiii. p. 326 (1859) ; Humbert & Saussure, Verh. 
z.-b. Ges. Wien, xix. p. 670 (1869) (nom. preeocc.). 
Orthomorpha, Bollman, Bull. U.S. Nat. Mus. 46, p. 159 (1893) ; and of subsequent authors. 
Antenne slender. First tergal plate wider than the head, semielliptical, generally with rounded angles; 
metazonites smooth, from the fourth to about the 18th with a transverse sulcus. Acels moderately well 
developed, with thickened borders carrying the lateral pores; posterior angle acute or subacute. Caudal 
process with sides converging and apex truncate. Anal sternal plate triangular. Sternal areas unarmed. 
Legs slender. Phallopod with its distal segment elongate and differentiated into femoral, tibial, and 
tarsal elements; the seminal stile arising on the upper (adoral or preaxial) side and guarded by an 
auxiliary branch forming a sheath which may be complicated by accessory branches. 
Type, O. beaumonti. 
Distribution. Oriental and Ethiopian Regions, introduced by human agency into 
other Regions. 
The name Paradesmus, Saussure, was originally applied to the following species :— 
Section I. P. carolinensis ; Section IL. P. klugi, P. erichsoni, P. picteti; Section IIL. 
P. beaumonti (Linn. Ent. xiii. pp. 325, 526, 1859). One of these must be its type, 
the addition of P. coarctatus to the list in 1860 (Mém. Soc. Phys. Geneve, xv. p. 297) 
not in any way affecting the question. Asa matter of fact this question was settled 
by Humbert and Saussure in 1869 (Verh. z.-b. Ges. Wien, xix. p. 670), who eliminated 
the members of Sections I. and II. respectively under the names HKuryurus and 
Pachyurus, and restricted Paradesmus to Section IL., making P. beaumonii its 
type-species. But since Paradesmus was preoccupied, Bollman proposed Ortho- 
morpha to replace it. Therefore P. beaumonti is the type of Orthomorpha and not 
P. coarctata as Silvestri asserts [Ann. Mus. Genov. (2) xvi. p. 198, 1896]. The 
importance of this conclusion comes in in the following way:—P. beaumonti was 
described by Le Guillou, and its characters are not sufficiently well known to 
enable a satisfactory settlement of its exact position to be reached. It may, in fact, 
fall into the genus to which I subsequently gave the name Prionopeltis (see Attems, 
Denk. Akad. Wien, lxvii. p. 559, 1899). If so, Prionopeltis will fall as a synonym 
of Orthomorpha and another name will have to be found for the host of species 
now by common consent assigned to Orthomorpha. But since P. beaumonti may be 
congeneric with the latter, it would be premature to disturb the existing nomenclature. 
I have therefore retained the name Orthomorpha for the following species. 
