Drosophila genomicists,

You may find useful material in this new orthology comparison of Arthropod
genes at http://insects.eugenes.org/arthropods/

euGenes/Arthropods contains computed protein orthologs among 13 species:
3 mosquitoes, 3 drosophila, 2 hymenoptera, 3 other insects, a crustacean
and an arachnid.

These can be searched by gene names, descriptions and IDs. You can also
select gene groups by presence or absence in a species. Find genes also
by BLAST, including PSI-BLAST, of the ortholog groups.

You can for instance find the 7 cases in 27497 groups where the other
insects, including Dros. pse. and Dros. moj., have a gene that Dros. mel.
is apparently missing (I think I've found most of these in Dmel's genome :)

You can also find these Arthropod gene pages via Google searches,
Google: daphnia drosophila ixodes gene homeobox
Google: drosophila aedes aphid gene ribosomal protein L13a

especially if you add these newer genome organisms others do not yet report.
Google searches are not as certain to pick up all the
arthropod gene groups as the search at euGenes/arthropods.