Brown Marmorated Stink Bug

In my last post I showed you some pictures of a Scentless Plant Bug (Niesthrea louisianica). Now I'm going to compare it to Halyomorpha halys, the Brown Marmorated Stink Bug. As I mentioned in the previous post, other than body shape, the main difference between these bugs is the color of the hemelytra.

To start off, let's review the characteristics of the suborder (Heteroptera) that these two species share. NC State University has a great site that breaks it down. I won't recapitulate that info, as you can read about it on your own, but I will provide a helpful diagram from the site:

These are the basic forms of the bugs in this suborder. The stink bug is on the bottom right and the scentless plant bug is directly above it. (The top left is probably a seed bug, the bottom left a leaf-footed bug). 

"Members of the suborder Heteroptera are known as "true bugs". They have very distinctive front wings, called hemelytra, in which the basal half is leathery and the apical half is membranous. At rest, these wings cross over one another to lie flat along the insect's back."  Again, the stink bug has obvious hemelytra, their being the same shade as the scutellum and pronotum (see below), while the scentless plant bug's hemelytra are as transparent as the wings.

The external anatomy of a stink bug:

hawaiidermatology.com

"Fore wing of heteropterous insects with anterior part partly sclerotized, the tip being membranous; hemielytra are laid flat when at rest, the posterior ends overlapping." http://www.inra.fr/hyppz/ZGLOSS/6g---253.htm#haut

a: hardened part of the forewing "hemi-elytra" (with 3 parts: embolium, corium and clavus); b: membranous part of the fore wing; c: hind wing (membranous); d: pronotum; e: scutellum.

Brown Marmorated Stink Bug

A quick visual comparison:

Scentless Plant Bug

And now the rest of the photos:

Unlike the Scentless Plant Bug, the Brown Marmorated Stink Bug is considered a true pest and invasive species. But please, unless you have a real problem with the bugs in your garden, let them live!

References:
http://bugguide.net/node/view/9806
http://ento.psu.edu/extension/factsheets/brown-marmorated-stink-bug
http://njaes.rutgers.edu/stinkbug/identify.asp
http://entnemdept.ufl.edu/creatures/veg/bean/brown_marmorated_stink_bug.htm

Hibiscus Bug

You may have seen this bug around your yard and, like me, assumed it was a kind of stink bug. Actually, it's not! After an hour and a half of struggling to find this bug's name, I'm now able to identify it as the Scentless Plant Bug Niesthrea louisianica, sometimes called the Hibiscus Bug because that plant is one of their hosts. Whereas Stink Bugs are members of Pentatomoidea, Scentless Plant Bugs are members of Coreoidea. The Hibiscus Bug's family is Rhopalidae, subfamily Rhopalinae, tribe Niesthrini. Although it is abundant, it doesn't damage plants.

As I see it, the most obvious difference between scentless plant bugs and stink bugs is that the sclerotized part of the latter's forewings (called hemelytra) is dark, matching the color of the pronotum, whereas the former's wings have almost transparent hemelytra.

References:
http://bugguide.net/node/view/52865
http://davesgarden.com/guides/bf/go/4480/
http://www.ingentaconnect.com/content/esa/aesa/1977/00000070/00000005/art00002