Linncean Society. 



477 



Read also, " Observations on the Genus Derbe of Fabricius." 

 By John O. Westwood, Esq., F.L.S. 



After noticing the recent memoirs by Messrs. Percheron and 

 Boheman on this almost unknown Fabrician genus, and its very 

 close relationship to Otiocerus and Anotia of Kirby, the author shows 

 that the Fabrician type of the genus D. hcemorrhoidalis is quite 

 distinct from the group described by the two first- mentioned 

 authors as its type. He accordingly restricts the generic name 

 Derbe to the typical species with the following characters : 



Derbe. Rostrum ad medium abdominis extensum, articulo apicali minuto. 

 Antennae breviores. Oculi subrotundati. Ala? longiores, angustiores, 

 costa anticarum ante apicem incisa, venis numerosis, longitudinalibus, 

 in medio venis transversis conjunctis, mediana ramos 10 longitudinales 

 emittente ; ala? postica? vena, postcostali 4-fida. 



In addition to the typical species and the D. nervosa, Klug, 

 Burm., the author adds the two following species to the typical 

 group : 



1. D. semistriaia, luteo-fulva ; alis pallidis costa. magis fulvescenti venis 

 nigricantibus strigisque tenuibus fuscis inter venas (nisi cellulis apica- 

 libus) dispositis. Expans. alar. lin. 16§. Brasilia. Mus. Westw. 



2. D. strigipennis, pallide fusco-lutea ; dorso thoracis et carina faciei 

 sanguineis, alarum venis fuscis strigisque tenuibus fuscescentibus inter 

 venas omnes, ad apicem alarum carentibus, pedibus albidis. Expans. 

 alar. lin. 14. Brasilia. Mus. Westw. 



Mysidia. Rostrum ultra pedes posticos haud extensum. Antenna? me- 

 diocres. Oculi rotundati. Alas breviores, latiores, pulverosa? ; anticae 

 integra?, venis paucioribus, vena mediana ramos tres emittente, ramo 

 medio bifido ; postica? vena postcostali bifida, aut trifida. 



The variation in the position and number of the veins of the 

 wings, affording a character of primary importance for distinguish- 

 ing the preceding groups, the author has at some length entered 

 into an examination of their normal state and direction, and the 

 manner in which they become modified. The following species are 

 referred to this subgenus : Derbe pallida, Fabr., (described and 

 figured by Percheron from the Copenhagen Cabinet as the type of 

 the genus), D. squamigera, Fab., D. costalis, Fab., and probably 

 D. punctum, Fab., D. testacea, Fab., and D. nivea, Fab., as well as 

 the following new species : 



M. albipennis, parva, tenera ; alis albis anticis puncto parvo ante me- 

 dium costa?, punctis nonnullis ad marginem internum venis trans- 

 versis punctoque ante apicem nigris lunulisque parvis marginalibus 

 fuscis. Expans. alar. lin. 8. Vera Cruz. Mus. Westw. 



M. lactiflora, luteo-albida ; capitis vertice et collaris margine antico 

 parum sanguineis, hujus margine postico et margine postico tegula- 

 rum albis, alis albis margine antico lutescente versus basin maculis 

 tribus parvis maculaque majori ante apicem nigris. Expans. alar, 

 lin. 12^. Brasilia. Mus. Westw. 



M. subfasciata, alba; alis fusco transverse nebulosis punctoque ante 

 apicem nigro ad basin area? parva? triangularis subapicalis venisque 4 

 transversis obscuris. Expans. alar. lin. Brasilia. Mus. D. Burchell, 

 et Soc. Zool. Lond. 



