February ,899.] FS YCHE. 3 1 9 



Maine. Pseudopornala brackypiera, Orpliiila aequalis to that of 42°, of 



Mecostc/kus lineatiis, 3felai/opIus Dicliromorpha viridis to the western 



minor, and Orphula aequalis extend part of 46°, of J\Iela>/op/iis scnddcri to 



even farther north, in most cases at the western ]iart of 48°. 



least to Woodstock, 14, Vt., Jaflrej, The distribution of the locusts is dis- 



II, and No. Conwaj', 10, N. H., tlnctly closer in agreement with the 



Fryeburg, 5. and Norway, 6, Me. The annual means than with the winter 



sole remaining species is noteworthy as means; perhaps a little closer with them, 



illustrating in a high degree the peculiar on the whole, than with the faunal zones 



susceptibility of many of the group to drawn from the distribution of the 



physiographical conditions, and its dis- butterflies. I greatly regret to have 



tribution may rightly be said to be been unable to compare it with the 



almost as much physiographical as summer means or with lines based 



climatal. This is Triinerotropis mari- on the laws given by Dr. Merriam, 



iirna, the sea-side locust, which is viz. — tbat northward distribution is 



restricted to the sandy sea-beaches of governed by the sum of positive tem- 



the coast from York, 7, Me., southward, peratures for the entire season of growth 



The only exception known to me is and reproduction, and the southward 



that of a small colony at North Haven, distribution by the mean temperature of 



36, Ct., on the sandy plains of the old a brief period during the hottest part 



sea-floor, now a few miles inland but of the year. 



only a few feet above tidewater. Of course discrepancies occur. These 

 Examining the positive evidence are probably due, in part, to insuffi- 

 o-iven above in connection with the cient data, but may be due to other 

 faunal and climatal map of New Eng- agencies, such w%,e.g'.. some unknown 

 land in Scudder's Butterflies of the factor, or the difference between the 

 Northeastern States we find a remark- annual mean temperatures and the tac- 

 able conformity in the distribution of tors stated above or to the possible con- 

 the locusts with the courses of the mean flict of these two factors between them- 

 annual isotherms, a conformity most selves, resulting in unconformable l-im- 

 striking in the western, more inland, its of two adjoining zones, distinguished 

 part of their courses. Compare, for by the overlapping or absence of char- 

 instance, the southward extension into acteristic species in certain sections. 

 Massachusetts of the ranges of Mecostc- As nearly as we can judge, however, 

 tluis gracilis -AwA Alelanoplus extremw; from the data at hand, these limits are 

 with the line of 44°, of Circotettix conformable in the case of the New 

 verriicnlatus and Cainnula pellucida England locusts except in eastern Mas- 

 into Connecticut with the line of 46° ; sacluisetts, where, also, the principal 

 the nuilhward range of Mecostethus discrepancy with the isotherms is found, 

 lincatits, Mclanoplus minor, and consisting in the absence from the 



