44 The Mechanism of EvoLUTioisr in Leptinotaesa 



BlOTYPE NIGROPUNCTATA StURM. 



Similar to signaticolUs (plate 2, fig. 2), but with elytra having numerous 

 large black punctations, which may or may not show arrangement in pattern of 

 ten irregular double rows ; punctures often confluent, giving the appearance of 

 longitudinal vittae. Appears also in experiment, most often as a dominant, and 

 when isolated breeds true; female sex-linked, but not uniformly so. (See also 

 Jacoby, 1883, p. 232, who had Sturm's specimens for study.) Recorded from 

 Cuernavaca, Cuautla, Estado de Morelos, Atlixco, Estado de Puebla. 



MULTIT/ENIATA DIVISION. 

 LEPTINOTARSA MULTIT^NIATA Stax. 



Myocoryna multitcrniata Stai, 1859. Ofv. af K. Vet. Ak. Forh., p. 317.4. 



Chrysomela multitwniata Stkl, 1862. Monog. Chrys. Am., p. 164. 



Leptinotarsa multitcrniata St§.l. Gemminger et Harold, 1874, Catalog. 

 Coleop., t. IX, pt. 1, p. 3441; Jacoby, 1883, Biol. Centr. Am., vol. VI, pt. 1, 

 p. 253; Tower, 1906, Inves. Evol. Chrys. Beetles, Gen. Lept., Carnegie 

 Inst. Wash. Pub. No. 48, pp. 7, 18. 



This species has given me more trouble in the effort to untangle its taxonomic 



relations than all of the others combined. It is a plastic, variable, polymorphic 



form, showing curious phenomena of heterogeneity which I shall discuss later. 



From present data I have arranged the species and its minor forms as follows : 



L. multita^niata St§,l. 



Habitudinal variation: multitcrniata Stkl. 

 Recurrent mutation: melanothorax St§-1. 

 Saltation: tacubayaensis nov. var. 

 Biotypes: 



multilineata StM. 

 obscura nov. var. 

 Habitudinal variation: intermedia nov. var. 



Saltation, melanothorax StS,l. 

 Habitudinal variation: variabilis nov. var. 

 Recurrent mutation: melanothorax StS,l. 

 Biotypes: 



Red hypodermal color. 

 Orange hypodermal color. 

 Yellow hypodermal color. 

 White hypodermal color. 



Habitudinal variett L. MUi.TiT^NiATA-MxrLTiTyENiATA Stal. 



Stal's description of the typical muUitceniata form, taken from his monograph 

 (1862), is as follows : 



" Ovalis, supra flavescens, subtus cum antennis, pedibus, maculis prothoracis, 

 limbo scutelli, sutura vittisque quinque, exteriore intramarginali, elytrorum, 

 nigra ; maculis pectoris limboque apicali segmentorum ventris flavis ; elytris 

 minus regulariter seriatim pxmctatis. Long. 10, Lat. 6f millim. 



" Patria: Mexico (Mus. Berol., Coll. Dohrn). 



" C. multilineata simillima, prothorace latiore, elytris regularius seriatim 

 punctatis differt. Ovalis, sat convexa, nigra, nitida. Caput sat dense, distincte 

 punctatum, vittis duabus obliquis, basi conjunctis, flavis. Antennse articulis 

 quinque apicalibus transversis, clavam sat distinctam formantibus. Prothorax 

 elytris nonnihil angustior, sat convexus, antrorsum sensim, angustatus, disco 

 parce, subtiliter, utrimque densius, subfortiter punctatus, flavescens, maculis 

 compluribus lateralibus lituraque media ut littera V formata, plus minus con- 

 fluentibus, nigris ornatus. Scutellum flavescens, plus minus late nigro-limba- 



