6 ' PROCEEDINGS OF THE NATIONAL MUSEUM. volxx. 



develope<l tepniiua, as the case may be ; bnt all the larpjer preiiera (except- 

 ing />nff/i//«off',s') and some of the smaller show considerable diversity in 

 this respect; the greatest difference between different members of the 

 same jnfenus obtains in the two largest genera: Melanoplus. where the 

 speiies may range from those with merely lateral pads to those with 

 tcgmina far surpassing the hind femora; and Podisma. where they 

 range from apterous species to those with tegmina lialf as long as the 

 abdomen, lint tiiis range is not confined to the larger g«*nera, for sev- 

 eral monotypic geuera {Dernlrotettir, PhoctnUotcH. and Ocdaleonotun) dis- 

 play a wide difference between different forms of the single si)ecies they 

 ])ossess, in the length of the tegmina, a differeiu-e which is also paral 

 leled or almost i)aralleled .iinong certain species of the genera Hespero- 

 tetfi.v, roili-smaj Melanojjiusj and I'aroxya^ and particularly of the genus 

 Mclainqilns. 



This last genus is of particular interest in this connection, for it is 

 subefjually divided between distinctly short winged and distinctly long 

 winged forms, which only rarely Ji])pear to be closely allied; yet in four 

 of tlie species, .1/, dmcaoni^ M. margiuatHs^ M.fami<itus.i'd\\(!i M.e.rtremus^r- 

 si)ecies in no way closely related — there is a marked dimorphism in 

 respect of the length of the tegmina, the first two being normally pos- 

 sessed of tegmina only slightly longer than the pronotum, the last two 

 of tegmina hardly as long, if as lorf^, as the abdomen, but all occasion- 

 ally e([uipped with tegmina distinctly surpassing the hind femora. 

 When, however, we compare these fully developed tegmina (Plate I, figs. 

 «, c, /, i) either with the abbreviated tegmina of the same species, as in 

 Jf. extremns (Plate I, fig. //), or with those of their nearest macropterous 

 allies, .]/. (/lafhtoni (Plate I, fig. h), M.paroxyoides (Plate I, fig. ^),and 

 M. horealis (Plate I, fig. ^7), as in the other species, we can not fail to be 

 struck by the common differences which separate these abnormal macrop- 

 terous tegmina from the normal tegmina of the genus. (See further the 

 tegmina of the type of the genus, M. femurruhrum, Plate I, fig. //.). 

 Instead of the regularly tapering form normal to the genus, the added 

 portion, which is largely the extension of the region beyond the post- 

 radial intercalary area, is nearly equal, giving the tegmina a consider- 

 ably greater apical breadth and a consequent openness of neuration, 

 besides a less ta|)ering form. What is further to be noticed is that this 

 apical breadth and openness of neuration is also the characteristic of 

 several cases in other genera where there is similar dimorphism in length 

 of tegmina, as in Dendroiettix querc.ns^ Podhma alpiniu and Phoetaliotes 

 nehrascensis (Plate I, fig. e). In Podismn the most abbreviated form ot 

 wing is plainly normal, and I am therefore inclined from these examples 

 to regard the abbreviated as the normal form in Dendrotettix, Phoeta 

 UoteSj^wd the species of Mela)ioplufi (except, of course, M. femur rubrum 

 here illustrated. The same, however, is not the case in Oedaleonotua, 

 where dimorphism of similar degree is found, and it is therefore prob 



